The wax came almost 100% from the cappings when we harvested honey. I had some from the previous year, and combined I was able to get a bit over 7 ounces. Here's a quick rundown of my process.
1) After squeezing as much honey as I could out of the wax, I washed it thoroughly in the sink, breaking it up with my hands. Then I used a large slotted spoon to dip the wax out of the water. I placed it on paper towels on top of newspaper and pressed as much water out as I could. At this point, the wax is very crumbly and sticky. I left it to dry overnight, putting it on fresh paper towels before going to bed.
2) I gathered the wax together into a ball and placed it in a clean, large soup can. I put that into a metal coffee can filled about half way with water and put it on the stove with a low flame. Since the soup can was still a bit light, I used a metal clamp to hold it to the side of the coffee can. Of course, if you have an old double boiler that would work very well too. Be sure to secure the can with wax in some manner so it won't tip over into the water. You DO NOT want water to get into the wax, even a few drops. It will create pockets throughout your wax and it won't look good.
3) While the wax is melting, I prepare a second clean soup can by taking a piece of an old t-shirt and placing it over the top of the can, securing it with a rubber band. Press down on the cloth gently with your finger so there is a slight depression.
4) When the wax is fully melted, pour it slowly into the can so the cloth filters out the impurities. It will drain through quite quickly, though a little will harden on top of the cloth. I quickly remove the cloth, even if there is still a tiny bit of melted wax on it, and pour the wax into the mold. If you wait too long, not a problem--simply take the can with the filtered wax and put it in the hot water pan for a short while until it is fully remelted.
Next season, I plan to keep a coffee can with me so I can keep the scrapings when I remove burr comb from the frames. I've usually just scraped it off my hive tool onto the cement blocks that serve as the hive base, letting the bees clean up any honey that might be in the wax, but I've read that that can promote robbing and attract unwanted insects or other pests. Instead, I'll keep the area cleaner and gather even more wax for projects like this.