Great post, thanks for the tip on the ChemSearch "yield". I'll have to look for it and get some. This is off subject, but I just used PB Blaster today. The Bendix starter drive on my old '54 Ford Tractor was all rusted up and wouldn't engage. Pulled the starter, removed the little pin that holds the drive on the shaft. The drive wouldn't budge, so I hit it with some 'blaster', waited a few minutes and gently tapped it with a hammer and off it came.