According to the info I have seen, 2000 grit.
Use a white scotchbrite and the Clean n Dull. Put the Clean n Dull directly onto the scotchbrite and go over half of the ball in small circular motions....apply as little pressure as possible. Allow the Clean n Dull to sit on the ball for 20-30 seconds, then wipe it off with a dry towel. Do the other half the same way. Once you have done the entire ball wipe the ball off with a damp cloth to remove any excess residue.
I hope this helps!!!
-EX-
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C-G Pro Shop (owner/operator)
Youngstown Ohio
Track Intl.-Amateur/Pro Shop Staff
www.trackbowling.com