I had one that I ripped the cots off this season trying to remove the helmet head. Luckily I didn't damage too far down, it did survive, but took probably an extra 3 to 4 weeks to get its first set of true leaves. I had one other that did not survive.
After that experience, I now just snip the edges of the helmet head with nail clippers and keep it wet for a few days till I see the leaves starting to push the shell off, and then I'll give it some help, but a lot of times it will push the modified shell off on its own in about 3 to 4 days after being clipped if I remember to keep it wet.
