(You can see this tip in action at CNET TV.)
Do your Firefox bookmark icons ever break? For instance, I have a bookmark to the CNET Intranet but the Last.FM logo is next to it. Not horrible, I know, but annoying.
Here's how to fix improper icons that, for one reason or another, may show up in the Firefox browser.
First you need to find the bookmarks.html folder for your Firefox.
In Windows XP for me, it's on a torturous thrill ride through the following folders: Documents and Settings - username - ApplicationData - Mozilla - Firefox - Profiles--a gobbledygook folder.
Make sure your browser is not running, then open the bookmarks.html folder in your favorite text editor.
My problems are in the Toolbar folder, so I find that section of the bookmarks.
I find the entry I'm looking for, in my case CNET Intranet, and find the term ICON with the = sign after it. The text after ICON is the offending image.
Highlight everything between the quotes and delete it.
Now save the bookmarks document.
When you relaunch the browser the offending icon should be gone.
To restore the proper icon, just click on the bookmark. The site should add it right back.