Brass
My brass jewelry are given a coating of lacquer to prevent tarnishing. Wipe the piece with a soft cotton rag after wearing and store in a plastic bag. Note also that brass doesn't like water!Keep it dry
Silver
As with brass jewelry, not plated silver too can tarnish. I include a cloth to clean them from time to time but you can use many DIY solutions for caring for them from time to time. Ask me for ideas!
Plated silver
Just use a soft cotton cloth to clean them from time to time and do not use silver polish or silver anti tarnish as it takes away the plating!
Generally, oils from your skin and the oxygen in the air are what accelerate tarnishing. It is preferable to remove the jewelry prior to cleaning, bathing and swimming.