Sorry Ross,
Any sort of cleaning solution will not only damage the gold rim, but it will also damage the coating of the silver....makes it tarnish faster in the long run, dulls it permanently and turns the gold an icky color. Take a good look a some of the strikes people try to sell on Evil-Bay and you will notice the difference in some strikes that people have "cleaned"....and then try to claim it as "mint condition"....groan....
All I have been able to do for some of mine, is put them in a tightly sealing Air-Tite and hope they survive.