I at one time had a large number of the red colored plastic cap tins.
I had also found a number of the hard rubber tins from the time period. (These don't normally survive today unless they are within a presentation case)
Removing the paper label, I would spray paint the plastic with a flat black and then coat that with a clear satin finish poly. (I do this with the actual "tin" cap containers as well to make them look more period correct)
Should the inside plastic cans still be a bit more red than you may like, darken it with some brown leather dye.
Just a suggestion on my part, but it makes up for a nice display.
My best,
Blair