What are common colors for WW2 era boxes and crates, i.e., ammo, radio, rations, odds and ends? I know that USA painted them OD and USN used grays; some US boxes were rather elaborately marked as shown with these ammo boxes on display at the UA Air Force Museum at Wright-Pat:

It appears that UK painted their crates "dog doo brown" and Germany used various grays and feldgrau. It seems like they also would paint some sand if in Africa.
What about big shipping crates for, say, engines, transmissions, big stuff? From what few I've seen in color pix, they were usually bare wood.
Any info/tech orders/photos appreciated.