Ernie,

We routinely polish the inside of the head and the top of the piston of our racing engines.

Some like to use Mothers metal polish, I prefer 0000 steel wool. Just do the inside of the head and the top of the piston, do not do the sleave or the sides of the piston, leave that alone. If you use 0000 steel wool take the piston out, and blow dry with compressed air to remove any steel wool residue after cleaning. Its very fine, but you still don't want it going through your motor.

I do this after about every 20 or so flights.