The principle of the chisel is the same as that of a conventional chisel, but rather than a pointed end, its tip is curved so that the wick is cut to perfection. This prevents the wick from producing soot and makes it burn more evenly. When the wick is properly cut, the candle's flame is also much more beautiful (yes, there is such a thing as an ugly flame!) and it prevents the formation of a sooty ring around the rim of the container. So your candle stays impeccable for the rest of its life!