by tarnish do you mean they are turning brown colored ?
Dayton makes a cleaner , but it doesn't remove tarnish and oxidation http://www.daytonwirewheels.com/store/defa...n+Wheel+Cleaner
There are products to do it though , but damn each and every wire would be a LONG time working on them
If you feel like going at the bumpers 1st I can definately recommend Maas polish cleaner .
The spokes though would be a real bitch to do one by one with it
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