Most old K people would rather you didn't polish it. The idea is that you have a Stradivarius cymbal that will be around in a thousand years and if every owner polishes it, it will be smooth before long.
If done judiciously (not like you need anger management classes) and only once every 25 years it probably isn't a biggie in my opinion. I would treat that one with care though and don't think it has to be shiny, 'cause most old K fans would rather see green than sheen.
I'll bet that's a great cymbal.
