Wondering why your candle flame is really tall?, emitting black smoke?, your wax seems to be burning really fast ? or the top of your wick has a mushroom top after burning? Or adding black stuff to your wax?
Most likely it's because you forgot to trim your wick!
You should always trim your wick after or before every burn, Also keeping the wick trimmer to ¼ inch at all times. You should never burn your candle for longer than 4 hours, you should extinguish the flame and let the candle come to room temperature, and trim your wick before relighting.
I personally trim my wick before lighting my candle. I use a slanted Scissors or you can use a wick trimmer. This special tool is perfect in helping you trim your wick to the appropriate length with a clean cut. I wouldn't advise using your fingers to pluck off the mushroom top, because you might pluck your wick off too close to the wax. Possibly making it hard to relight again.
Also a really important reason as to why wick trimming is important is that when you relight your candle and you didn't trim your wick off not only does it let off soothe and burns your wax, adding the burnt parts to your beautiful wax or causing your wick to curl and possibly starting a fire/ hazard.
Don't forget the importance of trimming your wicks !