I have used ashes from my pipes, but I think the reason most advise against it is because it doesn't burn completely like a cigar does. There are always particles of un-burned tobacco in pipe ash. But, I haven't found it to be a hindrance. The pipes that I've used it on are still working, and the mud is doing its job. I can't imagine using Dead Sea mud or any real mud, but some have suggested using fireplace mortar. I can't say how well this works, since I've not ever tried it. But, it seems rather drastic.