>>9109157For OD, I tend to use Russian Uniform for lighter dinks and scrapes and Vallejo's German Camo Black Brown for heavier damage, dabbed on with torn sponge, based on nothing more than 'it looks about right' - at least at small scale.
It's not the fanciest kit around, as I do have one foot squarely in /tg/, and I'm unhappy with the running gear, but here's one of mine to put my paintbrush where my mouth is...