If you've been bad, and you have several half melted candles, you can do this in order to release their energies and complete the spells they were intended for.
What you need: All half used candles, and lighter or lots of matches.
You can arrange the candles in whatever pattern (or non-pattern) you want. Light all of the candles and say :
It is probably best if you put the candles on a non-flamable surface, away from curtains and other combustables, for you may need to leave them burning over night. The stove top is a good place for them.