How to remove tarnish from OLD Silver wire?

Hello all Audiogoners,
I have some pure silver wire (solid core UP-OCC 99,99%) left that I bought 4 years ago from reliable German reseller.
I have still a couple meters left.
Now I need this wire for my XLR to RCA cables but I found that it`s now tarnished (yellow to black color on some cable areas).
I have googeled to find the solution in any possible way, but the only answers I will get, will lead me to pages such as: "how to clean a jewelery or silver coins".

Please let me know if there is any possibility to clean it as ordinary silver or high-end signal cable needs different approach for cleaning? Is there some special procedure/chemicals to clean such (high-end audio) silver wire?
At present I`m at the point to trash this silver wire and to buy a new (that probably acquire the same tarnish after couple years)?
Maybe someone can offer a solution for this?
I`m not asking only because of my lousy couple meters, but there seems no decent answer (on high-end cable point) anywhere over the internet. Therefore I`m sure that there is a vast amount of people who are searching answers for similar questions?
Everyone is most welcome to share their experience.