Re: Blocking FB cookies - Firefox Preferences
Privacy & Security
1 - accept third party cookies = never
2 - keep cookies = until I close FF (so they all get deleted when you close the browser*)
*for the few sites where you do want the cookies go to the site and click the circled 'i' at the left of the address in the tool bar and set accept cookies to allowed, these will then be kept until manually deleted
3 - check clear history when FF closes and check - cache, close active logins, forms & search history and off-line site data (no need to check the cookies box due to step 2)
4 - Use NoScript.
5 - there are new options which also allow you to deny location, notifications, camera, and microphone usage.
Some data like site preferences (preferred zoom, etc) does stay but can be clear at step 3.
Hope that helps.