"Everyone loves the smell of an aromatic candle. They bring comfort during a relaxing soak in the bathtub, fill your living room with the scrumptious smell of baked pie, and are lovely on the porch on a warm summer's evening. But what happens when the candle is too short to burn or the wick has disappeared, and you still have plenty of wax left over? Do you just throw it away? No! Here are a few ideas for making great use of that precious candle wax.
Make More Candles
You can recycle old candle wax and make new candles from it by melting them down. Here are a few methods you can try. <snip>
Microwave method - Remove the metal wick base from the candle by carefully prying out with a butter or steak knife, be careful! Heat the wax in a microwave safe container on high power until softened. Times may vary depending on the amount of wax that you have, so heat in 30 second intervals until you get a feel for the amount of time needed."
That's from: http://www.fabulousfoods.com/holidays/crafts/recyclecandle.html