I am looking for a way to combine small soap pieces into a larger bar?

Add water and let the pieces dissolve or get really soft in a closed plastic container. Once dissolved, take the lid off and let the water evaporate. If the pieces are really soft, press them together and then let the water evaporate.

Hint: when buying soap bars, take the wrappers off when you get home and let them dry out further. The bars will last longer, especially if you switch them out weekly and let them dry out.

Greetings. I have been doing this for years. Stitch up three sides of two worn face cloths to make a bag. Gather all your small soap bits and put them in the bag, then immerse the bag of soap bits into VERY hot water for a couple of minutes. As soon as it is cool enough to handle, twist the top of the bag to press out the water, and keep twisting until you can't get it any tighter. Tie it there, and let it sit until completely cool and almost completely dry. You should then be able to peel the bag away from the contents, which should be a more-or-less globe-shaped, solid piece of soap. Wishing you all life's best, and keep on gathering the crumbs!

Have you ever tr melting them d and pouring into a mold and let it dry ? Kinda like making a candle