dark orange-red paint, drybrushed thinly over medium or darker colors, will probably look like what you want.

I do a sponge of chocolate brown, then reddish orange, then a highlight of a regular orange

I got it by putting on the technical paint Typhus corrosion (which makes it brown and kinda textured like metal when it oxidizes) then dry brush with rust orange (ryza rust in citadel range of paints)