A few helmets from my collection.

This is my Captain's USN M-1 WW2 helmet. As was a normal way of preserving items around saltwater in the 40's-60's, the helmet was overpainted in shellac, postwar.
This German SS M42 WW2 relic was found by a highway crew in Russia.
I do not know the origin of the helmet painted red. I think it may be a USN Safety Officer helmet from a ship board fire detail (USN helmets and ID markings vary from ship to ship, ask any Navy vet). The yellow in "SO" is typical of ship primer coat. USN helmets were painted and marked with whatever paint was available on the ship. Some USN helmets are obviously done in haste and tend to be "sloppy" rather than neat.
The last helmet is a WW2 U.S., M-1, front seam, swivel bale with a "salty" WW2 Marine cover.