THE APPRENTICE GUIDE TO CANDLES
For the first burn make sure that you keep the flame alight for about one hour to allow the wax to melt right to the edge of the glass jar. This should avoid the wax from tunnelling.
Candles are a fire hazard, obviously. Place on a heat resistant surface in a safe location away from fabric furnishings and where they can’t be knocked over. Keep the space ventilated and the candle out of the reach of children.