<html> List: I've been coating the brass keypins on Yamahas as part of regular service for several years now.  I find that unless I do so, the brass seems to react with the moisture in the air and develop a sticky residue!  I have also noticed a black residue on the bushing felt which suggests to me the presence of copper oxide.  Once the pins are treated with CLP, and the bushings are treated with Teflon, the action remains glassy smooth.  I'm heppy to hear your testimonial Kevin!  I'll keep up with my CLP on key pins.  Seems to last! Larry Beach, RPT Vancouver BC, Canada <blockquote type=cite cite><blockquote type=cite cite>. . .The way I know CLP to work, and have demonstrated it to my own satisfaction, is that it works primarily on metal, not necessarily on felt. It seems to plate or coat the metal with a polymer type lubricant. The carrier flashes off, leaving the polymer. Some people don't like to use it on brass, like key pins or aggraffes, because if you store it in a container with a brass spout, it will react with the copper in the brass, and start to turn blue. The implication is that it will cause verdigris on brass parts. I have not found that to be the case, because it's the carrier that is reacting with the copper, not the lubricant. (And remember, the carrier evaporates.) . . . . . .   The way I really began to think about the action of the CLP, was when I kept tuning a Yamaha C7 for concert work. I would regularly mute off the back duplex area with masking tape, just so that I didn't have to listen to any extraneous noise while tuning. After several concerts, I noticed that I was getting a little noticeable residue on the strings there, and I thought that it looked "tacky" to let it go like that. So,  I put a little CLP on a small piece of cloth, and used it to clean the rear duplex strings. I then took a dry cloth and wiped the remainder off, buffing the strings to a shine. Two or three months go by; I'm called on to prepare the piano for a big concert. I go about my usual procedure, getting the piano ready etc, but when I try to apply the masking tape, It won't stick. I got my Naphtha out and cleaned the strings, it STILL WON'T STICK!  At this point I'm thinking "What IS this stuff". Then I found out about this technique of coating metal parts with a treatment other than teflon, and I think it clicked for me.  </blockquote></blockquote></html>