It is very important to use a special candle wick when dealing with gel candles. The candle master has to know how many threads should be used on the candle, depending on the amount of ml.
If the wick used inside the candle is too thick, the candle will start to soot. If the wick used inside the candle is too thin, it will hardly glow and it will not be able to melt the entire mass of the candle.
It is also very important to use the gel candle with a candle holder. If you do not have one, you can also use any ceramic plate that can extinguish the candle flame. The candle must not be exposed to moisture of water. This can bring up the petroleum smell from the burning candle.