sterling silver naturally oxidizes and therefore tarnishes. the best way to keep it from tarnishing it to wear it! remember to store in an airtight container when you are not wearing your piece. sterling silver should not be worn in water and should be removed before the application of lotions or perfumes to keep your silver's luster. to clean and remove tarnish, use a small amount of silver jewelry cleaner on a soft cloth and gently rub your piece several times. then rinse your sterling in warm water and carefully dry.
10k gold and 14k gold can be cleaned using gold jewelry cleaner or mild dish detergent in warm water. you can scrub your gold piece down with a soft brush, rinse and dry it. you can also use a gold polishing cloth. gold should be avoided in water with chlorine and when using household chemicals.