It would be worth trying for that reason alone. My salt bars always get thick ash too. I don't do anything fancy - just a little oxide for a tint of color. Maybe soaping fairly hot and moving fast. I use individual cavity molds. I think this is going on the to try listIf it gave enough working time, I'd bet it would help with the thick ash I get. Maybe cut the salt to 50%...... Hmmm.