if you got a tin lap with the machine then use that to polish. if you use this corian lap run it very slow and use 50,000 diamond powder and just enough water to make a mud to polish. i personally never use nor recommend diamond compound, it give a faults polished look as the compound grease fills the scratches. in rare cases when polishing very large stone facets i may add a drop of crystalub or mineral oil to the surface with the drop of water on the tin lap.