Other things I've read about lately: Johnny Farraj and Sami Abu Shumays describe a lot of stuff in their "Inside Arabic Music". The riqq (classical tambourine, the lead percussion instrument in the standard Arab ensemble) should be made of fishskin. And not just any fish - the ultimate is the skin of a Red Sea skate. And one kind of skin-bellied gourd violin should have its membrane made from the pericardial membrane of a water buffalo.

My wife's brother used to wallop people with pig bladders for a Morris side in Suffolk. This meant regular trips to the offal butcher.

The creepiest I've heard of is a Romanian folk clarinet where the "reed" is an eviscerated slug. Dunno if the eyestalks look up at you as you put it in your mouth.