All silver or gold tarnished pieces must be polished before placing them in a "tarnish proof box". Please note that many such boxes are not air tight as advertised, so your pieces may get tarnished anyway.
I prefer putting my polished silver jewelry in a ziplock bag with those "squares" that come w/ silver jewelry or a yellow Sunshine Cloth. It seems to keep the air out and tarnish, too.
You can purchase small ziplocks at the pharmacy section (usually used for pills), but great for earrings, rings and smaller pieces. Sandwich size bags work for necklackes, bracelets, etc.
***The best way to keep jewelry tarnish free is to wear them often and not save them for special times.