Hi, I have a box full of rancid/expired oils, and would like to use it up instead of throwing it out. If i were to do a hot process superfat at 0% for the expired/rancid oils, I understand that the soap might be dry to the skin. I was wondering if i could add in my cocoa butter ( its not expired) to the soap batter as a addictive after I've trace it or should i add it after its cooked? Should I add 5% cocoa butter of the total oil used? In the soap calculation, i will not include cocoa butter in the calculation. Is that correct? Thank you so much.