Hello Ladies - I really only use my old used candles for things like fire starters. However, if you don't make fire starters and if you have old pillar candles or votives, you could always break them up and use pieces in a wax tart warmer. Old container candles can be placed on small warming trays to get them melting and to use up every last bit of your fragrant wax. In the past, I have placed my larger container candles in the oven (on a pan) on the lowest temperature setting to let the wax fully melt. Once it's melted you just fish out the old wick and replace it with a new tabbed wick by carefully placing it in the center and keeping it standing there with a pencil or chopstick until it is cooled. This works great for those container candles that have only burned down the middle and left a lot of wax on the edges.
As far as remaking candles with used bits and stubs, I myself wouldn't want to sell them. Mostly because I believe you shouldn't sell candles that you haven't thoroughly tested. Used candles have probably lost some of their scent and may have bits of old burned wick in them so you lose a little quality there. Furthermore, what if your candle turns out so perfect that your customer wants to order more? You probably wouldnâ€™t have an accurate way of recreating that candle.
Nevertheless, candle makers themselves can use recycled candles all over their house. I know Iâ€™m always burning some sort of candle scraps, experiments, and definitely my flops.