We use natural wicks which are zinc and lead free. The wicks have a paper braid look and are designed to ‘self trim’ by bending at the tip while burning - this can look like a mushroom top. It is best to remove this before you relight your candle.
The cleanest and easiest way to trim your wick is with specially designed wick trimmers.
It is always best to trim the wick to approx. 0.7cm or just below the burnt mushroom top before you relight your candle. This will prevent the wick from smoking or sparking and make your candle burn more economically.
It's really important however to not to trim the wick too short, if this happens, it will result in the wick producing a small flame which won't be strong enough to melt the wax to the edges of the container and you will get tunnelling - when the wick burns down but you still have wax on the sides of your candle jar.