If you don't have the dedicated rocker arm resurfacing fixture that used to be optional equipment on most valve grinders, a narrow belt sander that places like Harbor Freight sells, with a very fine grit belt is a pretty good substitute. Use Dykem or Prussian Blue to monitor your progress while doing the resurfacing. Once the contact pad is smooth, use a crocus cloth belt to put a mirror polish on it.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!