If you’d like to preserve your online privacy then it can be a good idea to clear your Firefox cookies, but there’s usually a price to pay. Even if you’re careful, the chances are you’ll delete genuinely useful cookies, and be forced to manually log in when you revisit some of your favorite sites.
Install the Firefox add-on Biscuit, though, and cookie management becomes much easier. It allows you to mark particular items for preservation, which means you’re then able to delete just the unwanted cookies while keeping everything else.
Once Biscuit is installed, clicking Tools > Show Cookies displays a new dialog detailing your current cookies. And at its most basic, this works much like Firefox does normally: you can scroll the list, view particular cookies, then delete just them or the entire set.
You can also search the list for cookies you’d like to keep, however, such as your eBay login. Select and right-click these, click "Check", and you’re done -- clicking "Remove All Cookies" will delete unchecked cookies, but leave everything else untouched.
Sometimes you may actually want to delete all your cookies, of course, but the developer has thought of that. A "cancel cookie preservation temporarily" option makes it easy to wipe all your cookies on demand, while still preserving them in future.
Better still, there are a host of configuration options to help you get Biscuit working exactly as you’d like. You can choose to mark the cookies you’d like to preserve (opt-in), or delete (opt-out). Session cookies can be preserved; unwanted cookies can be removed when Firefox closes down, and you can even have the Tools > Show Cookies menu item hidden, preventing others from tinkering with your settings.
The default Biscuit settings will probably work just fine, then, but there are also plenty of tweaking opportunities available. If you need some flexibility in your cookie manager then Biscuit is worth a closer look.