The problem with jar candles and pillar candles is that the wick burns down through the center of the candle, its flame diminishes and the only light you get is above the candle. They just aren't real useful if you really need actual light from them. Dipped or tapered candles will be much more useful in an emergency situation. They are easy to make although the process can be a bit tedious.
My dipping can is an old spaghetti sauce can which I have put in a pan that has a few inches of water in it. The wax I have in there are all just old candle wax; edges of pillar candles or small stubs from tapers. Cook it until all the wax melts. This will take a while. Even after you think it has all melted, upon stirring you will find more lumps; be patient.