My parents recently moved so I was going through some of the stuff I left there and found a watch that I got for Christmas maybe six years ago. I stopped wearing it when the battery died and I am going to get it replaced so I can wear it again if the situation calls for it.
The thing is that some kind of patina formed on the metal strap (not the back of the watch itself, though) probably from the pencils it was stored with. My mother recommended to use toothpaste to get it off and that does seem to be working, but is there anything (preferably cheap) that would get the job done faster? Before you ask, I have no clue what type of metal it is made out of, but it wouldn't surprise me if it was a cheaper material.
Foaming bathroom cleaner. It's not necessarily cheaper than toothpaste, but I find that it works fairly quickly for cleaning metals of questionable origin without a lot of scrubbing.