CARVERS STROP COMPOUNDS Abrasive compounds make strops & wheels cut tool steel to achieve a highly polished razor edge. To use, rub compound bar into strop surface. To switch compounds, apply over previous. White, fast cutting, sticks best to surface. Yellow (sometimes called "knife makers secret" & yellow stone), cuts fast no residue(our favorite). Zam, fine finish sticks to surface. Red, finest finish, sticks well. Best Deal all 4 Compounds.