Sometimes it was mosquito repellant; but 99% of the time it was LSA (Lubricant, Small Arms). If a GI didn't have some LSA, he sure had to borrow some from one of his buddies (and that buddy would tell him in very clear words to start packing his own LSA!). Every weapon carried by GI's in Vietnam, from the .45 pistol to the M16, to the M60 and .50 caliber machine guns were semi or fully automatic weapons...and they NEEDED constant lubrication. If they didn't get lubed...they JAMMED! Machine gun belts of 7.62mm (.308 cal) and .50 caliber were constantly lubed prior to feeding into the guns. M16s and M14s were lubed (oiled) in the receiver groups (receiver housings). When the guns fired, a mixture of heat, and burnt gunpowder, all mixed with the burning oil to become permanently embedded into the GI's memory for years to come. That mixed with the scent of a tank's diesel engine and some crushed jungle leafs (vegetation) make for some memorable evenings.
US Army M1 steel helmets were not issued with cloth camo covers as were the US Marines fighting in the Pacific, during WWII. Consequently, soldiers didn't do to much writing on steel. The common thing was to paint their division patch on the sides of the helmets (1st Infantry Division, 3rd ID, 4 ID, etc.). In Vietnam, the US Army began, for the first time, issuing cloth camo reversible covers for the steel M1 helmets. At this time US Soldiers began writing graffiti on their helmets.
No
Leather, after 1916; steel.
Standard issue camoflage for US Soldiers came in the form of a "net" for their steel helmets, during WWII. Only US Marines were issued camoflage steel helmet covers as standard issue; during WWII. The Vietnam War was the FIRST war in which the US Army issued camoflage cloth helmet covers for their steel helmets, as general issue.
Very little or none at all apart from steel helmets
US Army M1 steel helmets were not issued with cloth camo covers as were the US Marines fighting in the Pacific, during WWII. Consequently, soldiers didn't do to much writing on steel. The common thing was to paint their division patch on the sides of the helmets (1st Infantry Division, 3rd ID, 4 ID, etc.). In Vietnam, the US Army began, for the first time, issuing cloth camo reversible covers for the steel M1 helmets. At this time US Soldiers began writing graffiti on their helmets.
no
North Vietnam also drafted it's men; captured NVA pith helmets had graffiti written on them that read in Vietnamese, "Born in the North, died in the South."
blue helmets
the shapes on the sides of helmets were used to identify a soldiers regiment the spade was (506th parachute infantry regiment)
All combatants in WWII were supplied with steel helmets. But only the US and USSR steel helmets survived into the Vietnam War era; both the US and USSR steel helmet "DESIGNS" served in the Vietnam War.
No
They wore helmets long before world war 1.
Not all gas masks are compatible with helmets, so some soldiers forgo helmets to wear their masks.
Leather, after 1916; steel.
Since the United States established trade relations with Vietnam in the mid 1990's, Vietnam has produced some excellent products; ranging from clothing, to Radio Controlled (R/C) model airplanes. The latest products, noted by the hobby minded consumers have been some accurate militaria equipment: British Empire Pith Helmets from the Zulu War period and the Boer War (1899-1902). These helmets are constructed from the same material that the original British helmets were built from; pith. The Zulu War helmets are offered in white covers, whilst the Boer War British helmets come in Khaki color. Of course, Vietnam also manufactures for sale their Vietnam War NVA pith helmets in OG (Olive Green), those come with a star insignia.
Like all soldiers in all ancient armies, Roman soldiers wore helmets to protect their heads