Although silicone grease is mainly use to lubricate rubber o-rings and moving parts of SCUBA gear, it has proven to be a great solution for snorkelers who have a mustache. Applying a small amount of silicone grease to your mustache before snorkeling will assist in reducing mask leakage caused by the mustache breaking the natural seal between the mask's silicone skirt and bare skin. Petroleum based products such as Vaseline do not react well with the silicone skirts found on most masks, therefore an inert grease such as silicone grease is preferable.
