These are the kinds of caps I used from the little 20oz bottles.
Here they are glued together with super glue.
Some 28mm minis for scale refference.
Basecoated with an olive green spray paint.
I added some hazard signes I got from this location: http://www.toposolitario.com/workshop/infinity_miniaturas/signals_n_panels.pdf
And here is the final results with a basic wash of dark burnt umber and some different colored sludge for a bit more color and detail on some of the containers.