What solution to clean silver and gold contacts?


Hello!

          I am looking for a product to use to clean contacts in my audio system. Contacts are mostly gold plated, but some of them are pure silver on pure silver.
         I do not want anything that leaves any kind of residue / contact enhancement product. I read on forums that some members claim these products improve the sound at first, but later degrade it. So in the end, they removed all of the contact enhancement product from the actual contact.
         Right now I am mostly leaning towards using pure ethanol alcohol, as I think all of it would evaporate.
         Thanks in advance for all of your advices.
audiobb
AudioQuest told me directly that tarnish on their silver-ended wires has zero impact on sound.  I've found that their silver-ended cables do tarnish slightly over a good amount of time (it IS silver), and if for some unusual reason after a good while I have them off and it's convenient, I'll remove the tarnish with a standard silver polish (Wright's Silver Cream)--very easy to do.  Of course I'm meticulous about being sure every trace of the polish is removed before reinserting.  But based on their guidance, I don't really care about it and could go probably indefinitely without paying attention to it.
Silver does not form an oxide layer. In fact it is very difficult to oxidize silver under ambient conditions. The black tarnish is silver sulfide which affects the conductivity. Depending on the amount of sulfur in your local environment, silver can form a mono layer of silver sulfide in a matter of minutes. 
Thank you all.
It seems that everyone agree that tarnish layer is silver sulfide, that does reduce conductivity, and therefore can affect the sound.
I prefer to clean it with something that does not leave any layer behind.
Would alcohol remove the silver sulfide?
Or at least, clean the contact from the dust safely?
What can remove it, without leaving anything behind?
ljgerens, are you sure that silver sulfide can form in minutes?

Unless you’re living in a Sulfur-rich environment(ie: around volcanoes/chicken coops/sewage treatment plants), you needn’t worry about sulfites forming in, "a matter of minutes"! https://www.powellind.com/sites/downloads/ProductAssets/01.4TB.080%20Switchgear%20in%20a%20Sulphur%2...Various conductivities/causes, concerning oxides/sulfides, discussed here: https://forum.audiogon.com/discussions/dielectric-grease-on-connection-ends/post?postid=1381403#1381... BTW: What stanleylocke and williewonka said, +1(each)