If you own resin rings, you are likely to encounter scratches and whatnot but TwoCraftyMules blog has a great tutorial on how to re-finish your resin rings so they become shiny again.
In a small container, mix up a batch of resin according to the manufacturer’s directions. With a flux brush or other disposable brush, lightly brush a coat of resin over the top and sides of the resin pieces. Use a light hand when doing this; only a light coat is needed to get the glossy shine. Any excess resin will form a pool around the completed pieces and will have to be sanded off after it has hardened.