I'm adding this after the fact: All ModelMaster acryl except for what you see in silver which is MM enamel and my wash. First coat was MM Acryl flat black, then green zinc chromate. Just that alone gives a nice effect but to highligh more details I washed everything with heavily thinned enamel burnt umber. When I do this I don't try to wipe away excess that isn't highlighting details because it gives a stained, dirty look to everything.
Just as a note to anyone planning on trying this in the future, I've had multiple hobby shop clerks tell me that this method will dissolve the acryl. It has yet to happen to me but I don't try to rub off the excess like most people do with panel line washes, I just leave it.