Now this is handy! I was trying to figure out how to get Gmail to forget a previous email username and password the other day and I came across Mission Data Blog. There they had a simple tip for clearing out saved form information in Firefox:

Go to the form where the mistake is.  Put your cursor in the text entry widget and hit down until the incorrect entry is highlighted. Now press shift + del … voila.

WOW! It’s so simple and so handy. I’ve been deleting saved stuff all day long from input boxes. Great tip and very useful.