My old German gunsmith friend staunchly refused to use any acid to arrive at a coin type finish. If it had been blued (engraving shows up very well)he would start with worn out 320 grit cloth, backed by files. Then he would switch to oiled steel wool, dipped into fine emery abrasive. working in small circles, he would blend and even the color, until he was satisfied with the appearance. As for myself, I just use steel wool, loaded with fine or very fine valve grinding compound. Clover brand is the compound available in my area. When finished, just flush the abrasive residue off and oil as usual.
Mike
