My personal opinion would be to clean it with the best quality silver polish you can find !! It will also clean brass and other metals !! However it depends on what you intend to do with these containers, their current value and age, and possible increase in value over the years !! If your intent is to sell them in the future,, I would say to leave them as-is !! Most buyers want to see that tarnish as proof of age !! My reason for cleaning silver, brass and other metals is that eventually that tarnish can eat through the metals surface leaving dark patches that can not be removed without expensive restoration work !! I do not recommend cleaning for anything with a historical connection but for everyday objects,, I would mildly clean,,,do not use anything that can scratch the surface !! Only use the softest of cloths and top quality polish and buff afterwards to a shine !!
Get others opinions here too,, that is only my opinion,, other have different viewpoints and reasons !!! Listen to all before you decide !!