How do I un-add a word to the dictionary used for spell checker (in Firefox 2.0, using Mac os x)?

I right-clicked an underlined word (misspelled), but accidentally clicked "Add to Dictionary" rather than choosing the correct spelling. How do I look at the words which I've added to the dictionary? I'm using Firefox 2.0, mac os x.How do I un-add a word to the dictionary used for spell checker (in Firefox 2.0, using Mac os x)?
There's an extention someone made to do that, or you could edit the persdict.dat file. (Which I believe is a plain text file despite it's extention.)

http://kb.mozillazine.org/Deleting_spell鈥?/a>

http://webdesigns.ms11.net/chromeditp.ht鈥?/a>

http://kb.mozillazine.org/Persdict.dat