Yes - that is still a good argument though thanks Jill.I know nothing about soap chemistry but, what about the chemical detergents and phthalate fragrances in their commercially produced liquid soap? Isn't that enough to make them switch?!
And honestly, I haven't noticed a difference in the scum level in my tub, it seems the same. Although, a few years ago, I had a glass shower door, used liquid soap and had to wash that shower door once per week, it was like looking thru a thick fog.