Silence of the Critters

I'm sure any of you who have had a critter (rabbit, guinea pig, ferret, chinchilla, etc.) for a pet knows how annoying it is when they drink from those cage-side-mounted water bottles. The metal marble clicking against the metal tube with every sip is enough to drive a smaller man than I to drink. In my case, it was enough to drive this Baker to think!

My idea is simple: coat the marble and the inside of the tube in rubber, like old mouse balls! ( I'm referring to computer mouse balls, now get your mind out of the gutter.) Not only would this go a long way toward silencing the drinking process, but it would also form a more leak- proof seal.