Oil leak, between flywheel housing and block

[JMBT]

Signature620 had said: “I usually hit the sealing face of these housings with an orbital sander then clean and reassemble it with a light coat of Permatex Aviation Sealant on both sides of the gasket.”

What grit disc do you use with the orbital sander? I don’t want to remove too much material but want to get the surface nice and clean.

Thanks! JMBT