This doesn't help with the bunging up the pipes issue (which I don't worry about), but I often use dessicated coconut in my 100% coconut oil (with 20% super fat) and coconut water soap. I mix some in for a bit of exfoliation and sprinkle some on top. I have a bar that I made over two years ago and it is as snowy white as the day it was made, no sign of brown specks or mould. It is my favourite soap. Only problem with it is that coconut oil seems to dissolve very quickly in water so it doesn't last as long as mixed oil soaps, despite being as hard as a rock. I can unmould it on the day it's made if I make it in the morning.