I know first hand that lots of people who wear brass colored badges on their uniform (police etc.) use 3M Tarni-Shield to keep them tarnish free for months. I used it on a brass jointed cue and it still looked good 6 months later. Brass-O only last days. It cost more but it works. The bottle I had lasted me about 3 years, and it was for brass. The newer bottles say Silver Polish, so check with 3M if it's the same stuff for brass.