Thanks, BadBobOK. If this isn't it, it may be dang close. All I have to do is smell it and I can tell if it's the right stuff. The older HD belts were more "rubbery" than today's more "platic-y" belts. So, they benefited from some sort of "lube". It really was not a "lube". More like a wax. Extremely thin coat was all that was needed. HD and Gates never admitted it, but some sort of goop was advantageous. With today's plastic-y belts, the need may not be as much, but the stuff was always nice to have handy in the tool box chemical drawer.