frockc,
Box finish is 1500 smooth on the GP2. In most cases if you try to sand a ball to 1500 it will end up a bit less dull than the balls do NIB.
If you apply pressure while cleaning the GP2 with a green scotchbrite, it will definately dull the surface of the GP2 down from where it was NIB. Applying as little pressure as possible just kind of breaks oil/dirt out of the pours of the ball.
Grey scotchbrite can be found at a store that sells auto paint and supplies. The easiest method may be to find your local dealer of Dupont auto paint, they will have them there.
I like the grey scotchbrite OR a worn out green scotchbrite because it will not really mark the surface of the ball much. I go in small circular motions.....it works like a charm.
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C-G Pro Shop (owner/operator)
Youngstown Ohio
Track Intl.-Amateur/Pro Shop Staff