As to comments that Citric Acid "attacks metals", I have never heard of this before (regarding brass). Most information I have states there is no damage, that the Citric Acid "passivates" the brass and helps fight tarnish (making it more resistant to corrosion). Perhaps there is some confusion with ammonia, which is harmful to brass. If anyone has any reference to Citric Acid being a problem please let me know. I'm only one of many using this cleaning process. And it doesn't leave my brass shining new, just clean.