You have banner ads in your browsing history? I'm not sure that I follow.
At any rate, look at the freeware CCleaner (originally known as CrapCleaner)
. As the name implies, it removes "crap" from your system, including logs, histories, cookies, temp files and all kinds of other leftover digital junk. It works on both Firefox and Internet Explorer, and will purge history, temp files, cookies, saved passwords -- anything you choose to "clean". As far as using the software, it should be straight-forward and user-friendly.