We all know that if you’re naughty, the risk is that Santa will leave a lump of coal in your stocking instead of presents. It’s not often that Santa follows through on this threat (although I think one year when she was a teen my parents DID put coal in one of my sisters’ stockings), but this lump of coal soap is a fun way to remind everyone that Santa always knows what you’ve been up to.

People also like activated charcoal soap because they say it helps remove toxins from the skin, so this coal soap is practical, too.

This coal soap is actually really easy to make, although initially I did try to make it with a white, opaque base. I had to add twice as much activated charcoal, and still didn’t get it as dark as the soap made with the clear base. So I’d definitely recommend sticking with a clear soap base.

After I was done making it, I realized that you could probably turn this coal soap into an exfoliating soap by including used coffee grounds like I did with this mint and coffee soap. It might even help add to the lump of coal effect.

Lump of Coal Soap

Materials

Clear melt-and-pour soap base
Activated charcoal capsules
Wax paper or parchment paper

Tools

Large silicone ice cube molds of silicone muffin tins
Cutting board
Kitchen knife
Microwave
Microwavable measuring cup or bowl
Spoon

Steps

1. Chop up your soap base and put it in your microwave-safe melting container. You’ll want to melt about 3-4 ounces per lump of coal, but don’t melt too much at a time, because it starts to solidify quickly. Don’t worry if you don’t have a kitchen scale to measure, usually melt-and-pour soap comes in a big block that’s divided into squares, and each square is approximately an ounce. Put the soap in the microwave, and microwave in 30 second increments until it is melted.
2. As soon as your soap is melted, remove it from the microwave and as quickly as possible, open capsules of activated charcoal and stir them in. I used about one 260 mg capsule per ounce of soap, but you can also just eyeball it. When your soap looks black, you’ve added enough.
3. Pour the soap into your molds. I used 2-inch square silicone ice cube molds and liked those the best, but I also made some with silicone muffin tin molds. You could probably also use regular metal muffin tins, or small disposable plastic cups.

4. After the soap has set (probably a few hours, but you can speed it up by popping the soap in the fridge or freezer), remove it from the mold and use a kitchen knife to slice it into rock-like chunks. I actually was going to stop at this point, but decided that the soap didn’t look enough like coal yet.

5. Take the pieces that you just cut off of the molded soap, grate or chop them up into small bits, then put them back into the melting container. Microwave until just melted, then quickly dip your rock chunk in to coat it, and pull it back out with a spoon and put it on wax paper or parchment paper to set. As soon as the soap is cool enough to touch, but before it has set (just a few seconds for me), press the surface with your fingers to rough it up and keep it from setting too smooth. If you’re happy with the soap at this point, let it cool, but if not, melt more soap chunks and dunk again.

Note: People have warned that soap with activated charcoal can stain white washcloths and towels, so watch out for that!

For packaging, I wanted little brown bags, but didn’t have any small enough, so I folded the little bags out of brown kraft paper, then stamped them. I think clear bags would make good packaging, too.