I did do a build thread with z rims with hair bleach..
The search bit on here is shite and you cannot put in search z rims
Anyway..
Black sets especially z rims used 800/1000/1500 grade wet and dry with soapy water.
Then Wd 40 ..
Looked like new..
The White set which was faded and patchy cream colour , I just used 1000 wet and dry..
Then used loreal oxdant creame 40% vol (hair bleach) brushed this on wrapped in cling film and left on washing line in the sun for 4 days as uv light from sun acts with the cream.
It worked a treat on the White looks like new now..
You probably could do this on tuffs just cover the flanges (oh mother) with Vaseline just in case