I always take it out after a couple of days,if it is not eaten by then it will start to decay..i know if it is a crab the molt has alot of calcium and minerals but i am not sure on other molts..
Same here. I took out a Sally Lightfoot mole the other day & I swear there was meat inside. My Tuxedo urchin has been carrying around a cleaner shrimp molt on it's back the past couple of days.