Oops, did you accidentally add a misspelled word to Firefox’s spell check? Don’t fret. You can remove it.

1. Open your application data folder. On XP or Vista, go to your Start menu and hit Run (or just press Windows-R) and paste in %APPDATA%\Mozilla\Firefox\Profiles; on your Mac, navigate to ~/Library/Application Support/Firefox/Profiles.
2. Find your profile folder, which by default should look something like xxxxxxxx.default.
3. Inside your profile folder, find the file called persdict.dat and open it up in your text editor of choice.
4 Now just find the misspelling, delete it, and you’re done.

While you have this file open, you may seed your dictionary with other custom words and proper names that the spell checker constantly flags as misspelled.

[ Remove misspelled words from your Firefox dictionary]

[tags]firefox, spell check, misspelled[/tags]