Why are fiberglass wicks better then cotton wicks? Unlike replacement cotton wicks, our fiberglass wicks will last indefinitely with normal use, saving you money and time in the long run. Our replacement wicks require only about 1/4" to 1/2" exposure from the torch or lamp. For best results, the fiberglass wick should be exposed just enough to provide a smooth and steady flame shape. If your wick is overexposed, the flame will be unsteady, ragged, smoke excessively and waste fuel. And 1/2 inch wick provide you a desired flame. Fiberglass wicks are not consumed during use, however, they may need to be replaced if contaminated with water or poor-quality fuel. You will find wick replacement necessary when switching between paraffin oil, torch fuel or kerosene, and remember to let a new wick absorb the oil in the lamp before you light it.