1) I took an old wine bottle, scored the bottom with a glass cutter
2) Then, dipped the bottom into a small pan of boiling water and
3) put the bottom of the bottle quickly into a deep bowl with ice water. The bottom popped right off. ( If you do this BE SURE to use safety glasses and gloves just in case the bottle cracks wild! - I haven't had that happen, but you need to be safe) I am using them for outside patio evening decoration or camping.