Haven't had any time to work on the plastic boys from Terra lately, but when working on a commission I decided to experiment with oils for weathering. Metallics were also tested to simulate battle damage. The entire process was very quick, really no more than a few minutes total.
While the effects are interesting, I like the current weathering and battle damage effects more. However, I'm considering using oils to weather specific, more mechanical and greasy parts on power armor and vehicles in addition to the current method. I'm also considering adding a very small amount of metalic chipping to the power armor, but I want to mull that over for a bit.