I'm going to try using Liquid Nails to permanently glue them on.
Use silicone. It'll never fail and is IMO, a lot less trouble. It's also available clear.
Not sure why any tube of silicone would say that. Silicone is traditionally used on non-porous surfaces, like glazed tile and glass. Windows, aquariums, etc. Silicone is the only thing that holds a glass aquarium together. Definitely don't sand anything down first, but just make sure the mating surfaces are super clean.
Home Depot, GE Silicone - doesn't matter which one you buy, whether it's Silicone I or Silicone II, whether it's Window and Door or Tub and Tile (has anti-mildew agents). Just make sure it's clear.
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