Auto-complete is a useful function in the Firefox web browser (and many other programs) which scans what you are typing and suggests ways you might want to finish the phrase. Fantastic! However, from time to time, my fingers end up providing all the right letters but necessarily in the right order (as my brain outpaces my muscles) and I end up saving a misspelling into the list. Despite aiming to keep my virtual working environment orderly this is a small bit of chaos I have put with for years but this afternoon I finally got round to seeking out the answer and it turns out to be even easier than making the mistake in the first place.
You simply have to use the cursor keys to select the offending entry and then press Shift and Delete. Voila! Now I can amuse myself over the next couple of weeks every time I start typing into a web interface where I have previously made a typing error and purging it from the system. I am sure there will be enough of them that I will get plenty of chances to reinforce this new bit of information and work it into my subconscious.