I used rattle cans (vinyl and carpet auto paint) it doesn't wash out like the others. you would want to weather around the shin tools ankle and pouch areas more.
Yeah, I play paintball... I don't know how effective that would be tho... I always came out covered in blue and yellow heh.
My friend offered to let me roll around in his oil pan haha, I considered it but that would cause such a mess... all the weathering on my suit was done with rattlecans and it looks pretty authentic, atleast to me.
El1te