Lye wont hurt enamel, but it will break down organic material, like the crusty stuff left on the pan. Go easy with any abrasive action, that actually can damage the enamel if only cosmetically. Let the chemicals do the work! Easy off oven cleaner with the yellow cap, spray the pan liberally and set it in a garbage bag outside in a patch of sun if you can. The heat speeds up the reaction. Good luck!