[CarWiz]

It's better not to mix compounds on your buffs. Since you're using only one compound, you only need one buff. Start the buff (polisher, grinder, drill, or whatever) and apply the compound to the buff. Move your item back and forth over the buff. Don't hold in one spot and don't use a lot of pressure against the buff--Let the compound do it's work. Work small areas evenly. For a piano key, you could probably work the entire top surface. When you start to see a shine in the item, ease up with even less pressure and sweep the area. Check for the finish you want. If it needs more shine, recharge the buff and repeat. Don't let the buff load up with compound or material. After about 4-5 charges, screed the buff to clean then recharge. For hard metals, you can go longer between screeds. Soft metals and plastic buffs need frequent screeding to keep from building up material and scratching your finish.

I prefer to use sewn cotton for all my buffs and regulate the pressure for different materials. I have six buffs that are dedicated to compounds and materials. I write the compound and use in Marks-A-Lot on the side of the buff as a reminder. (White, SS, Aluminum, Plastic, etc.)