Lapping paste is a mixture of hard abrasive particles in a suitable base. The base can be oil-based like grease or water soluble lubricant. The hard particles used are carborandum, aluminum oxide, silica or silicon carbide, glass, boron carbide etc. Lapping pastes are used for controled removal and are used for the close mating of surfaces and for removing rust and brightening a metal surface. The lapping pastes are graded from extra coarse to extra fine. The larger the grit rating of the lapping paste, the finer is the paste.