Since I finally received replacement grips for my S&W PPK, I can now test the original grips to try and find out which lubricant or cleaner caused the corrosion problems. My first three I will be testing will be Tetra Gun Lube, Tetra Gun Grease, and Hoppe's #9 Nitro Solvent. I have some clean areas of the original grips that weren't corroded, so I will put a small amount of each item in this area. I will make sure that they don't touch each other too. I'll report back on the results in 1 week (or sooner if I spot corrosion).