A good degreaser dish detergent will work fine, and not bother the plastic. I'd avoid any petroleum-based solvents. Maybe do it when the little woman isn't home - they get persnickety about such things. :nod:
Wally Mart is selling the Krylon 'Fusion' paint for plastics. I've heard good things about it, and it comes in OD green and tan, in addition to black, all in satin finish. Should make a good camo. I'll be doing the plastic bits on my bike with it soon.
Maybe afterwards a couple coats of satin poly-clear, to protect it.