Okay, first things first. Let’s start with the band and assume it’s made of gold. Since it is a relatively malleable metal, it can be polished down, so any scratches that have tarnished the band over time can be worn down. Platinum isn’t nearly as soft, but rings made of the metal can also be polished by professionals to remove scratches – it’s just going to take more time and effort, so assume that it might cost more, as well.
Diamonds, on the other hand, are nearly the strongest material known to man (almost as strong as the stare-down of a woman, if you disappoint her with a less-than-optimal engagement ring). They won’t scratch easily, but layers of dirt can accumulate on them and you’ll need to remove the grime. The real problem is with chemicals you come into contact with, like cleaning fluids and hair dyes.
But if you just need to remove oily buildup, there’s no need to seek professional help. You can soak the ring in a bowl with one part ammonia for every four parts of water – but only for ten minutes, no more. Other acceptable liquids for bathing rings in are vodka and warm soapy water, but only for half an hour, max. If you need to apply pressure, you can use a children’s toothbrush with soft bristles. That should bring back the shine at minimum expense.
