Agreed with Jonas on the soaking. I like to try and get it off as soon as possible before it becomes a pain in the rear. Start by soaking in lukewarm water for 30 minutes. If the shed isn't coming loose then I'd do another 30 mins and rub gently. Leaving old shed on can promote bacterial infections (not saying it will but it is a possibility). Be careful with the eyecaps if you haven't removed them before.