I have had very good luck getting the helmets to drop off by putting my finger in water, then letting a drip go on top of the shell. This makes the membrane soft again, and as it dries and shrinks up it falls off. The membrane is still stuck to the shell.
If it stays there too long, it might be worth a try. Don't try to pull it off, you take a chance on damaging the delicate cotyledons. (first tiny leaves)
If it stays there too long, it might be worth a try. Don't try to pull it off, you take a chance on damaging the delicate cotyledons. (first tiny leaves)