You can get the clear plastic ones or the felt ones from any hardware type store. They sell replacements. If the glass is set into wood the brown felt ones actually seem to blend in better. The clear plastic ones always look like snot or glue or something got under the glass. The clear plastic ones go nice for putting glass over a metal frame table.

I prefer the clear ones cause they're a little thicker than the felt. You can buy them at Home Depot or Lowe's and are usually hanging, about 12 to a card. They're usually used on cabinet doors to keep them from slamming wood against wood. ;o)

I assure you the clear ones do not look like "snot" or glue. Mine are barely noticeable.

LOL, mine are clear on a metal frame, and don't look like that "stuff". Actually, I can't see them because there is always something reflected in the glass. Sometimes I check to see that they haven't fallen because they are not exactly visible.

I use the ones that are rounded and look like hardened silicone, they flatten slightly once you put the glass on it, and they keep the glass better anchored, as opposed to the slick plastic discs or the felt ones, which only protect the glass but are slippery.

I used clear ones and for some reason when I removed the glass after quite awhile mind you, they had caused the wood where they rested to look lighter. I later was told that those rubber discs have some sort of acid in them that damages wood, especially if the wood is near a sunny window. Mine was not near a window however. I put the glass on the top of the table to protect it from my kids hoping that one day I could remove it, but now there are a number of strange looking spots.