It has a lower melting point than other waxes and won't break the glass. Add decorations, such as a vanilla bean, rose petals or some dried orange peel. Then add another layer of wax and decorations, continuing until the mold is full. It doesn't smoke, melts more easily, burns more slowly and has a lovely fragrance. Use real wicks when making candles, not kitchen string.
Wicks burn slowly and are much safer than string.
They cost only about 12 cents a yard. When using a flexible unwaxed wick, tie it to a craft stick and suspend it across the opening of the container.