Big Bends Nut Sauce Groove Luber Tuning Lubricant 1.5 cc Sweetwater D'Addario XLR8 String Lubricant Cleaner Don't Replace Your Strings Restore Them. Every time you play, your strings collect sweat, oil, and buildup that slowly kills your sound. Big Bends GEM TONE String Wipes bring them back TIL: The hole on the back of a tuner is for lubrication. : r Guitar What grease would you use to lubricate tuners on a classical guitar. I found using Petroleum Jelly (vaseline) too light. Any suggestions would be great.