Cleaning silver grillz regularly is very important, as silver naturally is prone to tarnishing. This is the dark oxide coating that occurs over time on the silver surface as it reacts with oxygen molecules in the air. What you will tend to notice is a gradual loss in the shine of your grillz. Most silver cleaning products contain toxic chemicals to remove this tarnish layer, however as grillz are worn inside the mouth we cannot use these products.
The best method I have found with silver grillz is to simply wipe off the tarnish layer before you wear them. This is a really nice cloth which easily cleans the tarnish layer. This product also adds an anti-tarnish coating on the other side of the cloth, which prolongs the shine of your grillz.
Why try fit in, when you could be custom made?