Ash in Soapmaking – What is it and how do you prevent it?

Have you had ash appear on your cold process soap?  When I first started making soap process method I did.  What I would do is spray distilled water on the soap and rubbed it off with a paper towel.  That gets abit tiring.  My last batch what I did was place cellophane wrap over the mold after I poured the batch into the mold and let it saponify.  That seems to work well.  In a recent posting from Lovin' Soap Studio called Ash in Soapmaking - What it is and how do you prevent it?  gives a tip of spraying rubbing alcohol on your batch.   Now I tried this but either I was not doing it right or maybe I was using the incorrect type.  If you read the posting you may figure it out.  But for right now I like the cellophane wrap the best.