Hi,
My silversmithing tutor said we should use a cap of household ammonia in tumblers to make them clean silver better, but please be aware that there is a serious health and safety issue here. For the last month I've had breathing problems since he did this in class and I breathed the fumes when taking work out of the tumbler.

I am asthmatic but did not know I would react to the ammonia (normally I have no problems with my asthma as I use a daily inhaler, and just occasionally react to a lot of cigarette smoke).

I don't know how widespread this advice might be so I'm posting it in case anyone else gets caught.
kind regards