Bottles on helmets of U.S. soldiers during the Vietnam War

That bottle is mosquito repellent ointment.

By the way, in fact, the things hung on the helmets of the US military during the Vietnam War were actually quite messy in detail. Most of them were small and convenient things that were easy to take during combat. There were also things hung on different occupations and different arms. different.

Take the U.S. Army and Marine Corps as an example: riflemen, the most common thing is to hang 1 to 2 magazines, apply ointment to the face, etc. Machine gunners usually carry a small ammunition chain (very short, usually no more than 20 rounds) for last-ditch use, mosquito repellent, etc. Grenadier, mosquito repellent, 40mm M79 grenade, etc. This is because different professions have different attire.

But generally speaking, most people bring mosquito repellent, Ace of Spades playing cards (representing death), amulets, cigarettes, etc. At that time, the Army's discipline management was stricter. Their helmets were issued with helmet hood straps (straps for hanging things on the helmet), and smearing on them was not allowed. The Marine Corps is very loose in this regard. They issue helmet covers but not fixing straps, so many soldiers cut the car straps into loops and put them on their helmets to hang things. Of course, their helmets also have messy paintings on them. Things like nicknames, anti-war slogans, slang, etc.