I use a 6" disc sander with a piece of 320 or 400 grit stick-on paper for polishing jobs like that. Hold the rocker square to the disc and freehand the radius of the tip against the sandpaper until it's smooth. Some valve grinders also have a rocker-facing accessory.
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!