How do I delete cookies? And just what are cookies, anyway?

Deleting cookies is an easy task. Whether it's absolutely necessary or not is another matter.

Cookies themselves typically aren’t as evil as most stories (and some anti-spyware tools) might have you believe.

A cookie is nothing more than some information a website can save on your computer that your browser then provides back to that same website the next time you return.

Seriously. That’s it. That’s all. That’s a cookie.

It’s what some sites use cookies for that has some people concerned and why you might care about things like deleting cookies, and perhaps even looking inside of them.

Cookies

It really is that simple: a cookie is nothing more than some information a website can save on your computer that your browser provides back to that same website the next time you return.

What that information is is up to the website. And that information is shared only with that website.

It works like this:

  • You visit some website, say reallybigbookstore.com
  • That starts with your browser requesting a page at reallybigbookstore.com
  • The server at reallybigbookstore.com responds with the page your browser is to show you and a some extra data. I’ll use “user=12345″ as the example, but it could be just about anything. This extra data is a ’cookie.’
  • The browser stores “reallybigbookstore.com,” “user=12345″ on your computer somewhere, and displays the page.
  • You spend some time viewing the page.
  • You move on to another page on that same site, perhaps by clicking a link to ”reallybigbookstore.com/tech_books.html”
  • The browser requests the page “tech_books.html” from reallybigbookstore.com and sends the cookie with that request (including “user=12345″) when it asks for the page.
  • The server does whatever the server does with the cookie and delivers the page to the browser to be displayed.

The important thing that makes all this work is that only cookies sent to you by reallybigbookstore.com will be sent to reallybigbookstore.com. This prevents one site from seeing the data that might be kept by another.

Example: Preventing endless logins

Cookies can be used for many things, but the simplest case is just remembering who you are.

For your sake.

What many don’t realize is every page you visit on the internet is, in essence, completely stand-alone. So when you login to a site like, say Amazon or Hotmail, there’s no inherent mechanism to pass along to the next page that you visit on that site that you are in fact logged in.

The result would be that each attempt to visit a new page on one of these sites would say in effect, “I don’t know you. Please login,” and you’d be faced with a never-ending series of login screens.

As you can see in the previous example, simply storing something that identifies you as a user is one way that sites can keep track and not force you to login for every page. The data actually stored is rarely as obvious as ”user=12345″ for security purposes, but contains enough information for the server to know who you are, the fact that you’ve logged in, and that you’re authorized to see the next page.

How cookies track

Much has been made about tracking cookies, but there’s nothing at all technically different between cookies that “track” you, and cookies that keep you from having to login over and over again.

Here’s the scenario:

  • You visit some website, say reallybigbookstore.com
  • That site contains advertisements provided by a large advertising network. I’ll use doubleclick.net for my example.
  • The advertisements that show on reallybigbookstore.com pages come from the servers at doubleclick.net.
  • That means that the doubleclick.net server can leave cookies on your machine just like any other website.

So far, you’ve visited a single site and the advertising network it uses has been allowed to leave a cookie on your machine.

Now you keep on browsing:

  • You visit some other website, say somerandomservice.com
  • Somerandomservice.com uses the same advertising network that reallybigbookstore.com does: doubleclick.net
  • When an ad is to be displayed on somerandomservice.com, it is fetched from doubleclick.net and the request sends any cookies for doubleclick.net to the doubleclick.net server. Even though the doubleclick.net cookies were created during your visit to reallybigbookstore.com, the cookies were in fact associated with doubleclick.net.

The advertising network now has the data to know that your computer visited both reallybigbookstore.com and somerandomservice.com, and as long as the pages you saw had ads, how often you visit each, and what pages you visited while you were there.

Multiply that by all the sites you visit, all the different advertising networks that exist and you can imagine that a lot of back-end data analysis can determine really interesting patterns of people visiting assorted sites.

Third-party cookies

As I said above, the doubleclick.net cookies were sent back to the server that they came from, the doubleclick.net server, even though the page you had requested was from somerandomservice.com. That’s how cookies operate – at a domain or server level.

Many browsers make a distinction between cookies for the sites you actually requested (somerandomservice.com), and the sites that are subsequently referenced as part of fulfilling that request (doubleclick.net). The later are called “third-party cookies.”

You are the first party, the site you actually request is the second party, and all the other sites are so-called “third parties.”

Most browsers allow you to turn off third-party cookies, meaning that the cookies created by third-party requests such as advertising networks are simply not created at all or are never sent.

Managing cookies: IE

To delete cookies, click on the gear icon or the Tools menu, select Internet Options and in the resulting dialog, click on the General tab. Now click on the Delete… button:
IE Delete Cookies control
As you can see, Cookies are one of the items that you can delete.

To view the browser settings for cookies, in Internet Options, click on the Privacy tab:
Internet Explorer Privacy Settings
Unfortunately, IE’s security model and its concept of zones are fairly complex (for reasons unknown) and to delve into it in detail would require more than a single, simple write-up. However, in this dialog, you can examine the privacy settings for Internet Explorer’s “Internet zone”.

As you can see above, third-party cookies are largely disabled in this example.

You can click-and-drag the slider to chose from a pre-define set of privacy settings or you can click on the Advanced button to choose a custom set of settings.

Managing cookies: FireFox

To delete cookies in FireFox, click on the Tools menu, and click on Clear Recent History. In the resulting dialog, click the little down-arrow next to Details:
Deleting Cookies in FireFox
Here you can select not only what to delete, including Cookies, but also select a specific timeframe.

To view the browser options for cookies, click on Tools, Options, and then in the resulting dialog box, click on the
Privacy tab.
Firefox Privacy Settings
In the Firefox will: dropdown in the History section, make sure to select “Use custom settings for History” to expose the more detailed settings available for managing cookies. Much like IE, you can enable or disable third-party cookies, create lists of exceptions, and more.

Managing cookies: Chrome

To delete cookies in Chrome, click on the gear or customize icon to the far right of the address bar and click on Settings. At the bottom of the Settings page, click on Show advanced settings…. Underneath Privacy, click on the Clear Browsing Data… button.
Chrome Delete Cookies
As you can see, one of the many items you can choose to delete is the collection of cookies, and like FireFox, you can specify a timeframe.

To manage cookie settings, once again in Show advanced settings…, underneath Privacy, click on the Content Settings… button.
Chrome Privacy Settings
At the very top of the resulting dialog box that appears are the settings to control cookies, including third-party cookies and any exceptions.

OMG! They’re tracking me!

No, they’re not.

Cookies! (The other kind.)

Cookies! (The other kind.)

Yes, they are, but … no, they’re not.

Here’s my position: they don’t care about you specifically.

Sorry, but you and I just aren’t that important or interesting to track as individuals.

Heck, the sheer volume of data alone makes tracking any one individual an incredibly difficult task.

What’s much more interesting is aggregate data: the data that says things like X percent of the visitors to reallybigbookstore.com also visit somerandomservice.com. Or data that shows that people that visit this page frequently are likely to respond to these advertisements. This type of tracking can also be used to perhaps prevent people whose online behavior appears to be similar to men from being shown advertisements designed for women.

You get the idea. They don’t track at the individual level, but they use the data en masse to do things like provide more highly targeted and interesting ads or perform market research.

That’s not to say that cookies can’t be misused; I’m sure they can.

It’s just that it’s typically a lot more work than it’s worth.

Unfortunately, some anti-spyware tools will flag tracking cookies – often any tracking cookie – as a form of malware. I simply and emphatically disagree. Flagging tracking cookies in that manner causes more confusion and concern that it actually adds any value. And it certainly doesn’t make you any more safer.

What should your settings be?

In my opinion, the default settings across all browsers are just fine. The examples above will let you see what they are, but I see no real reason to change them.

However, I know that some people feel differently and those of you might want to spend a little time diving into your browser’s cookie settings.

This is an update to an article originally posted : June 13, 2004.
Posted: December 6, 2012 In: Cookies

There are 43 comments:

  1. Anonymous Reply

    is it important to delete cookies?or im i suppose to delete cookies?

  2. Leo Reply

    That kinda depends on who you ask and how paranoid they or you are. My belief is that no, you need not delete cookies unless you’ve encountered a specific situation where you feel you need or want to. Most of the time you’ll never encounter such a situation.

    That’s what I do anyway.

    The flip side is that it’s typically safe to delete ‘em. A bit of an inconvenience results, as outlined in the article, but that’s about the extent of it.

  3. meagain Reply

    Hi Leo, I’ve deleted the temporary cookies, but there is a list showing of the sites that I’ve searched under C:Documents and Settings. How do I get rid of it?
    My father in law is coming to spend a couple of weeks with us this summer. He likes computers, and I really don’t want him to see that we occasionally look at the porn sites. Thanks, from A nice married lady who sometimes surfs out of bounds

  4. Leo Reply

    Make sure you clear all temporary internet files in IE’s options dialog. You may also want to visit Start, Settings, Taskbar and Start menu, Start Menu tab, Customize button, and then possibly the Advanced tab if there is one, to Clear the list of recently viewed documents.

  5. xialer Reply

    Hi, Leo i have the same problem as the other guy still doesnt work… i dont visit does sites but pop up and i click it : how can i fix it i try alot of ways control pad delete history and ur ways too. i dont want my family to find out and mistake me to go to those sites please help!

  6. none Reply

    oh almost forgot when i delete all the cookies it keeps coming back why? i mean once i select all it all comes back everytime… please help

  7. Kari Reply

    I am trying to get rid of the drop down box on sites like Google and Yahoo. It shows me everything I have ever searched and I am sick of starting to type a word to search under and a list of 100 words starting with the same letter pops up because I have searched those things in the past.

    I have deleted all of the cookies I can find. I have also deleted all temporary internet files.

    What else can I do? Is it even cookies I should be looking at….maybe I am out to lunch?

  8. Matt Reply

    Kari, that sort of information wouldn’t (or at least shouldn’t) be stored in cookies or temporary internet files as it is more related to the settings/functionality of your browser and not information from the sites themselves. However, since you cleared everything else out, you may still want to clear out your browser’s History log. Just for good measure.

    As for your current problem, in Internet Explorer, there is an “Auto Complete” function. Turning this function off will likely solve some of your troubles. The following site has instructions on how to disable Auto Complete, or even just parts of it:

    http://www.helpbytes.co.uk/acomp.php

    by the sound of it you need to disable autocomplete on “Forms”.. though I’d also recommend disabling it on “Usernames & Passwords” if it’s enabled. Those are the sort of things that shouldn’t be stored as it defeats the purpose of even having passwords. (*rolls eyes* “Thanks again Microsoft” … sorry, personal pet peeve :-)). You may want to disable everything depending on your preference, but keep in mind you’ll be typing out a *lot* of full website addresses if you do ;-).

  9. Walter Brennan Reply

    I have little computer knowledge when it comes to terminology and certain functions of the computer. I was just wondering if by deleting cookies it will make my computer run a little faster. I also get alot of freeze ups where it says internet explorer has encountered a problem and must close. I then have to start all over again and it is very annoying. This happens several times daily. I also even get another box that comes up when it freezes up. I will hit ctrl,alt, and delete and it will say program not responding and will have to click end program and then start again. Excuse my ignorance, as I am at a beginner skill level right now, but was wondering if this has anything to do with cookies or do I have to bring it to a professional and have it cleaned out. Thanks for your time.
    Sincerely,
    Walter

  10. Kris Reply

    I had 139 viruses on my computer all located within my cookies, so I deleted ALL of my cookies and now I can’t get into my email account. I get to the homepage, but when I type in my username and password it says that “this page cannot be displayed”…what do I do? As you can tell, I can’t get into my email account to check your response, so could you post it here?

    Thanks!

  11. husna Reply

    hi leo. i have this annoying problem and i hope you can help me. when i sign into msn hotmail and i see there’s mail for me i click it. but when its opened and i need to scroll down and then that’s when it freezes.
    please help me!!!

    annoyed!!!

  12. Ashley Reply

    Can I possibly delete “cookies” and not have to pay even a penny? Or how much $ does it cost to delete “cookies”? I tried going into my hotmail account & it said, “Unusable passport has been blocke by cookies”. What are cookies? Please contact me at ashleygalske@hotmail.com or jjlundy@htn.net. I hope to hear from soon!

    Sincerely,
    Ashley G.

  13. Tom Reply

    Thanks for the “cookies” information. I am still a bit concerned that I might end up deleting something I may need later if I delete cookies. However I have been accessing some websites that could get me in trouble at home, so I have deleted all my history and probably should get rid of cookies too (each time I stray into questionable territories). Tom

  14. Nikki Reply

    I have a problem searching for certain sites. I’ll type in my banks website or even something other than that… but if I dont type it correctly it says page not found and sends me to a porno site. Im sick of it! I dont go to that site but its embeded in my computer. Im not sure how to go about getting it out of my system. It used to be that if I typed something wrong or that site no longer existed, then it would send me to google or something on the lines of that. BUT NOT ANYMORE! Please tell me how to get this to stop.

  15. Beth Reply

    How do I free up memory when I try to print something and it says I’m out of memory.

  16. wendy Reply

    I am running out of space on my computer. Will deleting cookies help this.

  17. savio Reply

    i want to delete the cookies in ma google serch. so i tryed deleting the cookies throw tools from ie but the cookies in the google serch are still not geting deleted what showld i do now? plz can u help?

  18. GLORIA Reply

    The cookies on my browser are enabled, but I keep getting the “you must enable cookies…”, and I can’t open a few archives because of this.
    Thank you for your help.

  19. Aaron Reply

    Well, sometimes I delete my temporary internet files for ”reasons”. So today I went into them and they’re all gone. I only have 3 temporary internet files in there. I visited some websites, still the same 3. I did a system restore, still the same 3 files. If someone in my family goes into them and sees that there’s only 3, they’ll find out that I go on ”stuff” and end up deleting the Temp internet files. Why am I not receiving these files and how can I receive them again?

  20. Cynthia Ruth Butler Reply

    I am a 75yrs. old lady. Only use the computer for simple things like Picture storing, E-mailing. Ordering on line once in a while and stuff l;ike tat.Do I really need Cookies on my computer ? As I have deleted them sometime ago.

  21. Declan Gleave Reply

    hello, when i click on facebook on IE it comes up with a download box and an error message saying internet explorer cannot recieve files from facebook. However after a few times and i get on the website it sometimes comes up with lots of codes but sometimes i get lucky enough to go on. however once im on and try to do anything it says i need to enable cookies however i have tryed most methods using the tools, internet options way and enabling cookies but it still comes up with it. please can you give me some help?

  22. pato Reply

    We are sorry, but the system was unable to process your request because your web browser did not behave as expected. Cookies are required by this website in order to ensure a seamless user experience.

    Please make sure your browser has cookies enabled before continuing on your journey.

    it gives me that what I have to do???

    Enable and/or allow cookies. It’s also possible that your anti-malware software is interfering, so check the settings in your anti-virus and anti-spyware tools as well.

    Leo
    22-Nov-2009
  23. PS Reply

    I wanted an automated way of finding and deleting certain temporary internet files, so I can do it periodically. So, I wrote the following script in biterscripting that will delete selected temporary internet files.

    # DeleteTIF.txt
    # TIF=Temporary Internet Files
    # Deletes all TIF containing the search term.
    var str searchterm

    var str dir
    set $dir=”C:UsersUserNameAppDataLocalMicrosoftWindowsTemporary Internet Files”
    var str list
    lf -r -n -g “*” $dir > $list
    while ($list > “”)
    do
    var str file
    lex “1″ $list > $file
    var str content
    cat $file > $content
    if ( { sen (“^”+$searchterm+”^”) $content } > 0 )
    do
    system del (“”"+$file+”"”) 2>> “C:/DeleteTIF.err.txt”
    echo “Deleted file ” $file >> “C:/DeleteTIF.out.txt”
    done
    endif
    done

    Copy and paste the above script in file C:/Scripts/DeleteTIF.txt, start biterscripting (http://www.biterscripting.com ), enter the following command.

    script “C:/Scripts/DeleteTIF.txt” searchterm(“ad_client”)

    It will delete all TIF that contain the word ad_client (used by search engines to track a user’s internet activity). Then, I put the following command in my task scheduler.

    “C:biterScriptingbiterScripting.exe” “C:/Scripts/DeleteTIF.txt” searchterm(“ad_client”)

    That ensured that the selected TIF are deleted every day.

    That did it for me.

    You can try it – just make sure you use correct path to your TIF in place of “C:UsersUserNameAppDataLocalMicrosoftWindowsTemporary Internet Files” in the script – use double quotes around that path.

  24. Rupert D Reply

    I use the privacy tab to block tracking cookies. The list has just disappeared and is emptied every time I start a new session. I must have un-ticked a box somewhere, but which one? Thanks

  25. J. Sexton Reply

    Can I select what cookies I want to be deleted?

    Typically yes, but it depends on your browser. Use whatever steps are appropriate for your browser to *view* cookies, and typically you can delete them there.

    Leo
    05-Jan-2010

  26. Samantha Reply

    I was trying to upgrade my cell phone through ATT on the internet. Every time I clicked on the phone I wanted, it would take me back to my home page. I did call ATT to see if they could do it for me, but they didn’t have the same options as the internet did, but the person from ATT told me because I was unable to process my upgrade was because I needed to clear my cookies. I’ve tired to remove it, and I’ve followed your steps, but it doesn’t show the same as you are saying it. Oh and I just downloaded STOPzilla and it says I have infections and the infection name is “Cookies.” I have 25 infection’s from cookies. What do I need to do?

  27. Kevin Reply

    Shit I hate cookies..no matter what ya say they are dangerous in my mind.
    But what about LSO’s and Ever cookies ????
    There is not that much difference in speed in my opinion when they are deleted. Greed has always been mans downfall.

  28. snert Reply

    Can you edit the contents of the cookies with, say, Notepad? I’ll presume they’re stored where I can find and access them.

    I’d be surprised if you could edit them, but perhaps. Regardless, their contents it usually completely meaningless as it’s encoded data meant to be understood only by the web site to which it belongs.

    Leo
    08-Dec-2012
  29. steven Reply

    Has the time come that you have answered all the questions? A few months ago, i made a remark about defragging hard drives being old news and now we are onto Cookies, to me also old news, but not to the new computer users. Do you feel like your readers are running out of questions and you would get a lot of repeat questions, from people not using your search box at the top? ( I will not ask this again about old news, any more and accept it has to happen to new readers, which makes sense).

    There’s no shortage of new questions, however there’s also no shortage of people who are asking and need to see current answers to what many of us might consider “old” questions.

    Leo
    08-Dec-2012

  30. Ken in San Jose Reply

    For Chrome browser, in the content settings page, (Settings/ Show advanced settings/ content settings) click on “All cookies and site data” and it will take you to a page where you can delete selected cookies. In no time at all you can collect hundreds of cookies. Some of the cookies are good, you do not have to enter your user name when logging into a site. But a lot of the cookies are junk and not needed. So I delete these cookies to keep the number within a reasonable number of cookies.

  31. Anonymous Reply

    No personally identifiable information?

    Did you notice in the recent national election how both parties bragged about collecting info from an individual’s internet use?

  32. Bill Reply

    I don’t want to appear paranoid but I don’t think this is a coincidence. Yesterday I googled GPS units with US and Europe maps. This morning an email from Garmin awaited me with a “no postage” offer for any purchases from their on-line store.

  33. Sylvia Liney Reply

    I changed the settings to look exactly like your example & pressed OK. When I went back to check it was still showing the same settings, it had reverted back to
    Firefox will remember History, instead of what I checked, which was ‘Use Custom Settings for History’ Any idea what’s going on here? Why didn’t it save my settings?
    Also, I have a problem. After deleting some cookies, I can no longer log in to YouTube! The message is telling me that the site will not open. I can view stuff, but cannot add anything to my lists or make comments unless I am logged in….As I am a beginner, not sure what to do next….Please can you help?
    Thanks
    Sylvia

  34. Mark J Reply

    @Sylvia
    I don’t know what could be causing Firefox to revert to the old settings, but can tell you what’s probably happening with YouTube. When you log in to a Youtube the login information is stored in a cookie. When you delete the cookie, you are no longer automatically logged on when you go to that site. You now have to click on the Sign in button in the top right of the YouTube page. In order to be able to do this you may have to press F5 to reload the page, or if that doesn’t work you may have to clear the Browser cache.
    What’s a browser cache, how do I “clear” it, and why would I want to?

  35. Fred A Ferguson Sr Reply

    I have a set of pictures to run after not using computer for a short amount of time. It shows all my pictures an random order. The problem is that the cookies come up as a very small picture from the site I went to at one time. Shows name of site and small picture. Sometimes three at a time. Extremely good pictures then interrupted by these small inserts. When I look at my pictures they are no where to be found, so I assume it is a cookie. Was told there is no reason to remove cookies. Can I please have your opinion.

    • Connie Delaney Reply

      I’m afraid you have it all mixed up. You can’t see cookies, for the most part. They are a small piece of code that runs on your computer. It seems like what you are seeing is probably an icon of some sort.

      You also have one more thing to straighten out before you can figure out what is going on – and that is the difference between what is online (out somewhere on the internet) and what is saved locally on your computer. Try to straighten that out and ask your question again and someone here may be able to help you.

      • Fred A. Ferguson Sr. Reply

        Thank you Connie. Thank you for your reply as I will look into now. Always thought they came from internet. I see your point. Have a great day. Fred

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