Rebatching

Every once in a while, we have a soap batch that goes awry. Whether it is ricing or separation, or forgetting a key ingredient, or a batch that gets too thick before we could pour it, we have all had a batch of soap that could use a do-over.
I had a recent batch of soap that failed me. It came to trace nicely, but after I added the fragrance it started to curdle and separate. Previously when I’ve had this happen, I’ve been able to stickblend it back together, but this time it just wouldn’t stick. So, I poured the soap and hoped for the best…but when I pulled it out of the mold a few days later, the resulting soap was still soft and squishy, and the top seemed almost crusty. This was a 100% coconut oil soap, so it should have hardened up within a matter of hours from pouring. I double checked my calculations, and because I was positive the batch wasn’t just lye-heavy (which would have to have been tossed), I decided to rebatch this soap instead.
I’ve used this rebatching method before, and it works well. It’s easy to do, and I can use my slow cooker, which frees me up to do other things. I learned of this method from Amy of Great Cakes Soapworks. For my 2-pound batch of soap, I added ½ cup of water and ½ cup of castor oil. I don’t worry about shredding the soap, I just cut it into smaller cubes. I kept the slow cooker on low, until the soap was all melted and looked similar to hot process soap (applesauce stage):

I actually didn’t have to add any additional fragrance oil to this particular batch, I think keeping the slow cooker on low really helped to keep the fragrance intact. The rebatched soap was just as fragrant as the original:

To get a really smooth top, I overfilled the top slightly and then put a layer of clear plastic wrap on top and weighed down the top with a heavy object. Then, once the soap had cooled enough to cut, I sliced a thin layer off the top, so that it was even with the top of the mold.
Here is some rebatched soap that I made last year using the same method, with this one I added some soap chunks at the very end for interest and left the top mounded up:

Have you had to rebatch soap, and what is your favorite go-to rebatch method?