Nscaler711 - I like the "grimy-ness" that the oil chalks gave you. Is that stuff hard to work with? Does is stay on well without smudging? I have not "sealed" my chalk weathering with a dull coat since I don't yet have an airbrush. So now and again, I add a little color here and there to already weathered cars and engines. But I might try the oils if they work better and give more realistic results. I've even seen a guy at a train show use his wife's old eye make-up (on the trains - not himself) to weather the trains. He preferred it to chalks because it came in better and more subtle earth tone shades and was very difficult to remove - and therefore didn't need any dull coat since it hardly smudged at all (according to him). I might give both a try.