It is essential that the candle is burned for approximately 4 hours each burn, otherwise the candle will tunnel. Please be advised that tunnelling is quite literal, whereby a substantial amount of wax remains around the edges. In contrast, a small amount of wax on the edges, particularly during the first few burns is known as 'hang up'. As long as the candle care guide is being followed throughout the life of the candle, this hang up should dissipate as the candle burns lower down the vessel.