Unidentified oil cans

[Meekumslr]

Good evening,
I have posted this question on a few forums but cannot get a definitive idea of what my oil cans were used for.
I have a set of three oval oils cans which look to be WWI era but possibly WWII.
The cans are not marked and have brass screw lids.
I thought they looked like machine gun oil cans but cannot find anything on the internet to research them.
Has anyone any idea?
Many thanks, Neil.

[NCA]

I have some of these..exactly the same except mine have small brass plates soldered on stating the capacity:I have pint, quart and Gill sizes.I don't think they are military due to lack of any markings.I hope this helps.