We bought a lot of clear, glass candle holders for our daughter and son-in-law’s wedding reception. I saved them to loan to friends, but the only problem was wax left in the holders. I found that one of the best ways to remove old wax was to put the holders in the freezer for a few hours. Then I took the holders out of the freezer, turned them upside down, and the wax fell out. I put the glass holders in the dishwasher to get out any wax residue, and they looked good as new!