On the Plastic CAVs (and any other mini) - I dip in Simple Green, then rinse and let dry. I don't prime plastic - from Reaper, they say NOT to prime the plastic minis, just wash, dry, and paint.
My daughter (13) and I just painted a couple of the wrecked CAV tiles - I dipped them a couple of weeks ago and rinsed them off (dab dry with a paper towel), Painted up without any issues.