The no-sandpaper-on-particle rule was to prevent the particles from being sanded smooth.  Mostly softer particle types are affected.  I would say that it applies just as much particle pearls as solids.

If you're looking to adjust the surface on your particle or particle pearl ball, you may want to fire off an e-mail to the manufacturer or one of the staffers here about what type of stuff to use on it.  Some can be done with sandpaper with no ill effects.  Others are better done with Scotchbrite or even Trizact (though that's mostly older Brunswick particle balls).

I think most people would recommend a six-sided sanding pattern, where the ball is rotated to six different points during sanding.  Whatever grit you want can be used.  Lower grits for earlier, smoother reads; higher grits for later reads.

SH

The original surface of depth charge is 1500grit polished. It can be reached by using Storm Step1 and Step 2 after sanding with 320 grit sand paper.

However, I experienced similar things after I tried to resurface mine.
(I did it after about 150 games)
Whatevet you do, do not use high gloss if you would like to have the original surface back.

Burgundy pad and non grit polish (like Track Magic Shine) will do close. Still a bit more lenght. (I did 6 sides, all 30secs)
Green pad and 600 grit polish worked well also, but smoother and a bit less backend.

Hope this helps,
Burak

storm recommends using scoth-brite pads on their particle balls/

Thanks for all your reply, I have resurfaced it with green pad in cross direction because I want to recover it from a wet sanded by nonsence proshop guys. after that I polish it with columbia 1200grits and 3m finesse II. the surface look good and tracky, I can see the underlying matte finish with high gloss. my friend will try it today will let you all know the result. thank you very much again for all your advise.