I've been using Flitz off and on for several years to clean and polish small brass instrument parts. Sometime I wander away from it and try other polishes and cleaners, but I always come back to Flitz and I haven't found anything that's better. It does a very good job in getting rid of tarnish spots in brass and that's my main use for it.  It does take some elbow grease and maybe a second application for deep tarnish spots but it works better than other polishers/cleaners for this particular purpose.