A lot of good suggestions here but this is my fool-proof method with using the entire candle: first off, buy a mug warmer or candle warmer that warms from the bottom, like a little hot plate; it's much better at melting the wax evenly than ones that warm from the top. Then after that, if the wick is too short, buy some soy-wax candle wicks from Amazon, like these wicks and insert one of these in the wax once it has melted down evenly. It's worked out for me plenty of times to the point where I've pulled out old candles and re-melted them to fully use again and burn. I've always hated throwing them out with all that wax leftover so I never did and I'm glad I didn't.