I save all of my bevelings and soap scraps to make a mechanic scrub soap. I treat mine like rebatch.
My recipe/method:
In turned off crockpot, Soak 20 oz scraps in 4 oz water overnight. This is just enough water to lightly dampen them and help them soften, not turn them into a soggy mess. If your scraps are relatively new you can skip this, but most of my scraps are 3+ years old (don't judge me).
Turn on crockpot to low, allow scraps to melt for 20-40 minutes. This depends on your crockpot, my new one takes a bit longer than my old did. I want about half the scraps to be melted leaving some scraps as confetti in the soaps. I use a high amount of blue and green in my soaps so my rebatch colors to gray which works well for this.
When melted sufficiently, turn off heat, add 1-2 ounces of liquid soap (I use handmade because I have it, you can skip this or add more water), 2 oz fine pumice, and fragrance (I like CC Blood Orange). It's usually a nice pourable consistency, although if you don't add more water or liquid soap it doesn't pour as well. Stir well and place in mold. This fills my 6" loaf mold very nicely. Set for 12 hours before cutting.