I take it you are talking about very thick mud, not just mud color on surfaces. I have not tried this, but have seen it written up. One can find colored powder/dyes to add to plaster and spackling compound at hardware stores. Get a brown/tan color, add appropriate amount to spackling or plaster of paris and trowel it on.
I was not clear about the desired end result - do not want the mud build up to be as would be found on a tracked vehicle i.e., tank, that would dig in deep and accumulate large volumes.
Really looking for slight to modest accumulation - which I suspect your recommendation would accomplish - applied in moderation.
Did not want to try something on a nearly finished model and have it not work as expected, or ruin the model.
The thickened enamel paint may be the best way for me to proceed at this point.
I also need to build a diorama for this model - the Italeri 40 mm Bofors, as installed on the east bank of the Rhine near the Ludendorff bridge, early March 1945.
My dad was there and part of a 40 mm gun crew.
Never having done a diorama, although having seen many find end results - is the next big challenge.
Mostly not sure how to create the basic foundation - know that some use plaster covered styrofoam, or plaster covered crumpled newspaper - need to do more research.
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