First, I want to say I'm not an expert or even an amateur candle maker. I have not made candles since I was a kid making sand candles at summer camp. But while on a quest to clean out and use up what I have, I came across a bunch of partially used candles that were no longer very... attractive. Rather than pitch them, I decided to recycle them into new prettier candles that smell good. Also in the spirit of using what I have, instead of buying wicks w/ the little metal discs I decided to try using some cotton string and pop tabs. With a little trial and error I declare the experiment a success!
Step 1: Gather supplies
You probably have all or most of what you need:
Some sort of stick (to hold the wick upright while waiting for wax to harden)
Some cotton string
Something to mold the candle in (jar, bowl, old Pringles can, etc.)
Scissors to cut wick
Optional supplies not pictured:
Crayons (for color)
Step 2: Melt the wax
I would have used an old tin can to melt the wax, except that we just hauled them all to recycling. So I'm just going to hope my bowl will come clean! Put the candles into whatever you're melting them in and suspend it over a pan of simmering water and keep close watch on the wax till it melts. Once the wax melts, you will want to remove any old wicks and papers (the ones stuck to the bottom of the candles) carefully. I used a chopstick to do this. You could also carefully (the wax will be HOT) strain the wax through a mesh strainer, but I didn't bother.
At this point you can add scent (I used scented oils I had already) and color ( I added a couple of broken crayons). I didn't measure ~ just added till I liked the scent and color.