Can You Recycle Soap Scraps?

Can you recycle soap scraps? That’s the question I asked a soap-making friend. Her response was, “Try it and see.”

Well, I’m not into “try it and see” if I can find someone who has already tried it. So I looked online and learned that yes, you can recycle soap scraps.

But no one says what kind of soap. I had scraps from four different kinds of soap with varying compositions, colors, and scents. So of course I wondered if I could combine them. Would the ingredients mix? The colors nicely blend? The scent be reasonable? My only recourse was to “try it and see.”

Saving the Soap Scraps

When soap came in uniform rectangular bars with flat sides, recycling scraps was easy. We just “glued” a scrap to a fresh bar by wetting the scrap and pressing it against the wet bar. In those days we never had soap scraps. Today soap comes in many sizes and shapes, making this process more difficult.

So, being ultra frugal, I started accumulating scraps until my 2-quart jar was full. Then I figured it was about time to try recycling the scraps into new bars.

Cooking the Soap Scraps

First I put the scraps through a food processor to break them into smaller pieces. Then I covered them with water in a large pot and brought the whole thing to a boil, which I then reduced to a simmer

After I stirred for only about 5 minutes, the scraps started sticking together. Some of them melted into a pudding, which rose to the surface. The bigger pieces sank to the bottom.

With more patience I could have cooked the scraps long enough to melt them all. But I was more intent on making something useful than making it pretty.

I let the “soap soup” cool slightly, then poured it into a 6-inch by 11-inch by 3-inch flexible Tupperware container coated lightly with olive oil to aid with unmolding. The surface remained covered with small bubbles, which I dispatched with a light mist of rubbing alcohol (using a spray bottle of eye glass cleaning alcohol from the optician).

Cutting the Bars

Forty-eight hours later, when I thought the soap was firm enough to remove from the mold, I turned it upside down onto a cutting board. Unfortunately the surface was still a little too soft, so a bit stuck to the cutting board. No serious damage, but the bars don’t look quite so smooth.

After another forty-eight hours the soap was firm enough to cut into bars. You don’t want to wait too long, as cutting gets more difficult as the soap releases moisture. I cut mine into 12 pieces, which ended up being about 2 inches by 3 inches and 1 inch thick as they dried and shrank.

To provide air circulation I placed the bars on plastic mats, which are actually separators that came with a set of deli storage containers. I didn’t want to use metal cake cooling racks, as I wasn’t sure the moist soap might corrode them.

As you can see, the different types of soap separated into attractive layers. The result actually looks good enough to eat!

Then Wait and See

And now came the hard part: Wait and see. Bar soap takes a long time to harden so it won’t turn to mush in the tub. In fact, when we buy soap, we immediately remove the wrapping to let the bars dry out as much as possible so they last longer.

At first I was skeptical that my mix worked, because the top layer was quite a bit softer than the bottom layer. But as moisture evaporated, the soft layer hardened nicely.

And contrary to my misgiving about clashing scents, the bars have a gentle and pleasant scent. And the color? Well, it could be better. But after all, it’s just soap.

Fresh soap can be used any time it’s firm enough to handle. But it lasts longer after most of the moisture has evaporated.

Accordingly, about a month after I cut the soap into bars, I selected a bar and began weighing it once a week. When the weight was the same two weeks in a row, the bars were ready to use.

So, yes, you can recycle soap scraps of all kinds, even mixed together. And with just a little time and effort you will end up with fresh bars of free bath soap.