unhelmet

verb2

1. •
   To remove the helmet from.

   • In spite of all that Durward could say of the slightness of his hurt, he was compelled to dismount, and to seat himself on a bank, and unhelmet himself — 1823
2. •
   To take off a helmet

   • Due to security protocols—ones I had devised—I had to unhelmet at the front gate and a guard with a slavering dog met me in the circular drive. — 2005