Exactly how you delete cookies depends on which browser you’re using. Here are steps for four of the most popular web browsers:
Internet Explorer – Open the “Internet Options” panel and select the “General” tab. in the middle of the panel you’ll see options to delete cookies. Click the button and your cookies are gone.
Firefox – Head to “Tools”, click “Options”, and click the “Privacy” icon. In the top field, select “Use custom settings for history”. This displays options for treating cookies and other privacy information. If you’re serious about stopping cookies, be sure to check out the CS Lite add-on, which offers excellent cookie and privacy controls.
Safari – To delete cookies in Safari, head to the Safari menu and choose “Reset Safari.” A dialog box will pop up, giving you the option to delete all sorts of data; make sure “Remove all cookies” is checked and hit the reset button.
Chrome – Click the wrench menu and select “Options.” Then click the “Under the Hood” tab and look for “Privacy,” where you’ll find the cookie settings section. To delete all cookies from the list, click “Remove all.”
Opera – Select “Tools” in the Opera menu bar and click “Delete Private Data”. Next, a window will pop-up about “Delete Private Data” and then you’ll see a option called “Detailed Options”. Click that and check-off “Delete Cookies”. After doing that, make sure everything is correct and click “Delete”. Congratulations, you’ve deleted your cookies on Opera.
Keeping Cookies out of your browser
OK, you’ve deleted the cookies you’ve accumulated as you surfed around the web, but how do you keep them out? The most flexible way is going for a whitelist approach – this means telling your browser it shouldn’t blindly accept and store each and any cookie sent to it. Instead, you tell it which websites’ cookies should be accepted, and all other cookies will be rejected automatically. Now obviously this requires a bit of work on your side, but since your browser will remember your decisions and you won’t ever have to deal with unmanageable numbers of cookies again, it’s worth it.
Firefox – Choose “Preferences” in the “Edit” menu and go to the “Privacy” tab. Select “Use custom settings for history” in the drop-down menu under “History”, uncheck “Accept third-party cookies” and “Accept cookies from sites”, then click “OK” (or “Close”) to save your changes. At this point Firefox won’t accept any cookies, unless you define exceptions from this policy. This can be done with the “Exceptions…” button on the Privacy tab we just left, but you really should install an add-on like Cookie Monster or CS Lite instead. These will place a button in Firefox’s main window that allows you to change the cookie permissions for the current site without digging around in the preferences. Clicking said button will give you three options (worded slightly different depending on which extension you installed) – accept (permanent) cookies, accept temporary (or “session”) cookies, and reject cookies for the current website. We don’t need the reject option since that’s what Firefox does by default now, so you’ll be using the two “accept” options. If you allow temporary cookies, the website can set cookies, but they will be deleted when you close the browser – good enough for most websites. You should only allow normal/permanent cookies for websites on which you actually need permanent data storage – e.g. websites you want to stay logged in on across browser restarts.
Opera – In the Menu Bar, go to Tools, Preferences. Go to the Advanced tab, and go to the “Cookies” section on the left side. Set this to “Accept cookies only from the site I visit”. This means the browser will only accept cookies from the specific domain of the web site you are on. So, for example, if you go to eBay.com, Opera will only accept the cookies from eBay.com specifically, and will automatically deny any others, such as any cookies banner ads might offer the browser. If you don’t wish for Opera to automatically accept every cookie from every site you visit, you can check the box that says “Ask me before accepting cookies” at the bottom. Since most web sites only offer one or two cookies from the specific domain you are visiting, this isn’t as overwhelming as having to accept or deny every single cookie offer.
Some browsers offer an option to ask you for permission whenever a website tries to store a cookie in your browser, but given the sheer number of cookies that you’re bombarded with on the average website, this option is better left turned off unless you’re feeling particularly masochistic.
Almost all of the browsers listed above also support some kind of “private browsing” mode, which make your browser much more incognito by denying cookies and not keeping track of where you go (or keeping your browsing history). Note that in case of Internet Explorer you’ll need to be using version 8 or later to use private browsing.
Other data storage mechanisms in your browser
DOM storage – a newer feature aimed at web applications, provides much greater storage capacity than cookies (several megabytes). At least in Firefox, it is subject to your cookie settings, and can also be disabled by opening the address about:config and setting dom.storage.enabled to false.
Flash cookies – Adobe Flash has its own cookie-like data storage feature, and it can even be (ab)used to respawn normal cookies you deleted (see this paper). It does not obey your settings for cookies – you have to use Adobe’s Flash Settings Manager to configure it.
There are however several utilities which will delete your Flash cookies. For Safari, try the Cookies extension. On FireFox, there’s the BetterPrivacy add-on. Both allow deletion of Flash cookies (and even the folders that hold them) upon quit.
In the Future
Still, the future of cookies and online privacy looks bleakly Orwellian. Already sites are turning to Flash-based cookies and other tricks that make it even harder to cover your online tracks.