Hi - Just in case this may help someone. Years ago I bought some Green Clover lapping compound in maybe 6 different grits for 12 to 15 dollars for a 10 once can each. I then realized later that I could get silicon carbide and aluminum oxide from lapidary supply shops in many size grits from 75 to 50,000 for 6 and 7 per pound and pay just a little more for smaller amounts - mix it with a dab of a dollar a tube Ultra Bright tooth paste and I found it a lot less dirty and messy. And one can color code it with some food coloring from an Easter Egg coloring kit to help keep them straight. You may be surprised how it will shine up a dark bore.