Actually you can clean around 300 or so between 2-4 sheets. Just roll them around in between them, then sorta gently pick the whole thing up (BY THE CORNERS AND TOGETHER FOR GOD'S SAKE!!!) and roll them all around inside it. That cleans off the majority of the paint.
I would laugh if I didn't feel sorry for the kid. Stupid mistake, yes, but an honest mistake made for simply not knowing. They happen. Don't think for a second all of you haven't done something like that, just not necessarily with paintball. Yeah, literally flushed money down the toilet, actually attempt to chug liquor to cure thirst, get talked into doing a strip dance while totally stone drunk, various inexplicable tattoos and piercings, involvings with steam irons, superglue, gasoline, petroleum jelly, house/car paint, solder.... To err is human, to get it on videotape/camera is comedy or lifelong blackmail.