These earrings can be washed gently with mild soap and a soft cloth (don't use a silver cleaner or polish- it could remove the patina and harm the pearls). I recommend keeping the piece stored in a plastic bag or in an anti-tarnish jewelry box when not in use.
Your purchase will come in a small jewelry/gift box with a strip of anti-tarnish paper inside to help keep it looking new.
See the matching necklace here: http://www.etsy.com/listing/89634989/seashell-and-pearl-pendant-necklace
These earrings are also available in shiny silver: http://www.etsy.com/listing/89866718/shell-and-pearl-sterling-silver-stud
See the earrings without pearls: http://www.etsy.com/listing/70807056/seashell-stud-earrings-dark-silver