Found this neat little program about a week ago. It does all kinds of stuff in the way of cleaning up your cookies, history, and usage tracks. If you're a privacy nut, you'll like it. I use it for Firefox and IE. It supports Mozilla, Firefox, IE, Opera, and also takes care of some Windows usage tracks like recent documents, history, word document history, media player history, etc. What I like about it is being able to set protected cookies. You can view your current list of cookies, pick which ones you want to save, then clean the left overs. Each time you use it, it remembers which one's you saved. Once you set up a saved list, you can clean out your cookies in a matter of seconds when you're done browsing. 1.23mb download.
To set it up to work with Firefox or Mozilla, click on the tabs Mozilla or Firefox, depending on which one you use. Then click the button manage profiles, and pick your profile. If you don't have custom profiles within Mozilla or Firefox, pick the one that ends in .default. Then go into Manage Cookies and make your save list. When you're done, click close. From here, look under the title Select Firefox/Mozilla Options and check what you want it to clean. I keep mine on clean history/typed url's, clean autocomplete, and clean cookies. Once you're done, click Clean Checked Items!
After this initial setup run it's pretty simple. Each time you want to wipe the cookies, start the program, click your browser's tab, check Manage Cookies to see if there are any you would like to save, then hit Clean Checked Items.
There are a ton of programs out there like this one, but I've found this one to work pretty well. Give it a shot if you're interested.
http://www.buttuglysoftware.com/CleanCache3.html