Removing Cookies

A Cookie is a bit of code that a website asks your browser to store for it. Each Cookie consists of a ‘key’ and ‘value’ pair, and is provided back to that website whenever you visit it. Cookies are generally quite small, so typically the ‘value’ part will be an ID number, and the parent site will look up any information it might have on you by matching this ID with an entry in a database. This information might be stuff that you have knowingly entered (what items you have added to a shopping cart, for example) or it might be background (which pages have you visited on the website?).

Cookies are sent back to the website by your browser, so it 'knows who you are'. Many browsers let you decide whether or not to return the cookie to the website, and so allow you to control how much information a website can pick up about you.

In many ways Cookies are a good thing, they allow us to set up shopping carts or stay logged in (it would be annoying to have to submit a password for every page you wanted to see). Your browser will not, however, tell you each time a Cookie is issued. The transaction is hidden, and it can pass on a lot of information about you...

If you visit more than one page on a site, because the site can track your browser through the Cookie, it can start to build up a picture about your interests, and might use this to suggest other content that might be of interest to you.

Even the fact that you have visited the site is enough to suggest that you are interested in what it has on offer, and it might be useful to chase you with adverts to get you back. Clever use of ‘third party Cookies’ allows exactly this sort of activity.

Many countries have legal controls on passing personal information between organisations, but Cookie ID numbers are viewed as a ‘grey area’. While the ID number given to your browser when you visit a site may be arbitrary and ‘anonymous’, the collection of information on what pages that ID has visited does provide some telling personal information about you. Third party Cookies, which can track usage over a wide number of sites, will allow the parent or owning company to build up quite a detailed picture of what your Cookie ID has been up to!

Social websites may track you on external sites if these display timelines etc.

Social Media sites work by sharing personal data, Cookies set by these sites can be picked up by widgets (timelines and other features) in other websites, and report back to the parent when you visit them. In this way these sites can track your wider browsing history. Social media sites will be able to link this history to you directly, because you have given them your personal details.*

If you do not want to give Social Media sites your browsing history, you should delete any Cookies set by them. (Sorry, this is a pain, as you will have to login to them next time you want to use them, and may not be able to tag interesting content directly to your Social Media Profile). In the defence of Social Media companies, you get what you pay for. The business model for these companies is not getting paid by your subscription, but in knowing you (their users) in intimate detail. The ability to sell on this information to advertisers is what allows them to offer their services to you. If you did not read their privacy policy when you signed up, maybe you would like to check up now...

FaceBook Cookies Policy

Twitter Privacy Policy

* I have worried in the past about requests by many platforms for my address book, and always avoided doing this. Giving them my personal details is up to me, giving them someone elses details (i.e. the details of everyone in my address book) is illegal by my reading of the old Data Protection Act (never mind the stiffer requirements of the new GDPR).

Cookies are an essential piece of web architecture, it is only when they become invasive, or pass on information without your knowledge or understanding, that you need to take action. To do this effectively, however, you will need to know a little bit more about them; there are three principle types of Cookie:

First Party Cookies are set by the website you are visiting itself, and can only be viewed and used by that site. These are commonly used to allow you to stay logged in to a site, or to remember your preferences on that site.

Many sites rely on advertising revenues that use third party Cookies to target adverts effectively

Third Party cookies are set by the website on behalf of another company (the 'third party'). When the third party has agreements with many websites, these Cookies can be used to track browsing activity across all of the participating websites. This provides a lot more information about your browsing habits, and is commonly commercialised by allowing companies to serve targeted advertising to your browser.

Session Cookies are a special type of ‘First Party’ Cookie, they are the least invasive, as they are only kept for a short time on the site’s server (did you have to login again after a period of inactivity?), they will also be deleted by your browser when it is closed. Session Cookies allow the site you are visiting to recognise your browser as you go from one page to another on the website. They may be used to keep you logged in to a site, keep track of what you have added to your shopping cart, or remember whether or not you prefer a larger text size to read the site comfortably etc. Blocking session Cookies is likely to make many sites unusable!

A good browser will allow you to block Cookies by TYPE. Third Party Cookies probably don't offer much benefit for you, and a blanket block of these will greatly reduce 'leakage' of data between the sites you visit and any of the big search engine giants or Social Media sites. You should be aware, however, that many sites rely on advertising revenues that use third party Cookies to target adverts effectively (i.e. put something you are likely to be interested in on the page!).

Stopping your browser from accepting Third Party Cookies may stop the leakage of your personal date between sites*.

Some browsers go further, and allow you granular control of Cookies by site - so you can decide who you are happy to have information about you. This offers you control, allowing sites you like to make some advertising revenue, but does require a bit of effort!

*Other types of tracking technology: You can control Cookies using your browser (see 'Managing and removing Cookies' below); you have a lot less control over your IP address, and security agencies and others may use this to keep tabs on you. In theory you should be informed if a (civilian) site is using your IP address to track you (in the EU this is a legal requirement). In practice it is impossible to know that this is happening directly, you can only use inferrential techniques ('they must have been tracking me to know that'). You should assume that IP tracking accross the public network is within the capabilities of the security services.

Click on the menu in the top bar (three dots in a vertical line) to open the Settings menu. Click on the ‘Advanced’ option at the bottom of this page. Click on ‘Clear browsing data’ at the bottom of this block. You have the option of deleting ‘Cookies and other site data’ - be aware that this will only clear this data if it was collected in the selected time range (by default, Cookies you have picked up in the last hour).

Be aware that the 'Do Not Track' feature does not stop sites from tracking you - most sites will not notice this is set. There is no means to manage Third Party Cookies, which are most invasive, or prevent given sites from setting Cookies. As a consequence, Chrome cannot protect you from being tracked from one site to another short of clearing all of the current Cookies ('All Time'), then removing any Cookies you pick up after every site you visit...

If you are worried about personal privacy, this is a poor browser to use. Comment

Go to Menu | Options and select ‘Privacy & Security’. Under ‘Cookies and Site Data’ you can ‘Remove Data’ - deleting all Cookies in one go, or ‘Manage Data’ allowing you to select which sites you do not want to retain Cookies for. Note that Firefox has advanced options to manage how your browser uses Cookies; you can filter which Cookies to delete by site, for example. Comment

Click on the cog icon in the browser control bar to go into settings (care, msn also has a cog icon towards the top of the page, this is NOT the cog you want!). Click on ‘Internet Options’. Click on the ‘Privacy’ tab. Under ‘Settings’ click on ‘Advanced’. You should now see options as to how IE will manage common Cookie types. You can block all Cookies, Block Third Party Cookies, or Block NO cookies. NOTE you have no option to delete cookies for given sites ‘selectively’. See our notes on ‘Types of Cookie’ to work out which option might be best for you. Comment

Go to the menu (three dots … icon) and select ‘Settings’. Select ‘View advanced settings’. Under ‘Privacy and services’ there is a ‘Cookies’ option. Here you can block all Cookies, Block Third Party Cookies, or Block NO cookies. See our notes on ‘Types of Cookie’ to work out which option might be best for you. Comment

Click on the ‘O’ (top left of the browser window) and select ‘Settings’ (you can also access this using the keyboard Shortcut ‘Alt+P’). Click on ‘Privacy & security’ in the Settings menu. Under the ‘Cookies’ heading you have a range of options as to how you would like to manage Cookies generally, including an option to block Third Party Cookies by default. You can fine tune this in ‘Exceptions’, and you can delete Cookies set by specific sites in ‘All cookies and site data...’ Comment

Opera is not a commonly used browser, but it does offer a number of interesting features. It is the only browser that currently offers a VPN service built in. This allows you to disguise your IP, and coupled with careful Cookie usage, would enable you to avoid tracking by (most) commercial sites.

In the browser tap the three dots for options, find ‘Settings’ in the menu and tap on this. Under ‘Advanced’ tap on ‘Privacy’. At the bottom of this list is an option to ‘Clear browsing data’. On tapping this you get an option to retain some Cookies from Google and some other major sites, so you should not have to log into these again.

Be aware that the 'Do Not Track' feature does not stop sites from tracking you - most sites will not notice this is set. There is no means to manage Third Party Cookies, which are most invasive, or prevent given sites from setting Cookies. As a consequence, Chrome cannot protect you from being tracked from one site to another short of clearing all of the current Cookies ('All Time'), then removing any Cookies you pick up after every site you visit...

If you are worried about personal privacy, this is a poor browser to use. Comment

You can manage Cookies through the main ‘Settings’ icon (cogs) NOT through Safari directly. When you have opened Settings, work down to ‘Safari’ and tap on this to open browsing options. In the ‘Privacy’ group you have options to ‘Accept Cookies’ and to ‘Clear Cookies and Data’.

The tools for managing Cookies are a little crude. Refusing to accept Cookies will improve your privacy, but is likely to make some sites unusable. Comment