I was writing on the other topic about ring boxes/ cases.. Someone asked me about keeping tarnish down on their rings..

First make sure your case you keep them in is clean!. Make sure you give the rings a good wipe down before you put them in.. Also make sure the case closes nice and tight...

On this topic it shows about adding a 'silver cloth' on the top of your rings when you close it. There is a link to a good silver forum above.. These silver cloths can be gotten off eBay if your having trouble finding them..
IF you have a few rings that are getting black from tarnish you might want to try this. Again make sure everything clean 1st and case closes tight.. I would use the cloth , check often,,then after the first year I'd throw it away and put in a new one..