Step 1: Buy a small pan from the Dollar Tree. Put a toothpick in the pan and then place the jar on the toothpick. This keeps the jar from bouncing when the water boils. Pour water in pan. Bring the water to a soft boil. Wait patiently until the candle wax melts.
Step 2: Put a glove on your hand so you don't get burned. Pick up candle jar and pour melted wax into a can.
Step 3: Wipe out candle jar with paper towels.
And there you have it - a quick, simple way to clean out those nasty jars so you can use them to store your crafts supplies. :)
p.s. besides candle jars, I use all kinds of other jars too.