do not throw against dirty or rough surfaces or corners/edges
Throw them against walls and windows and watch the splat then, like magic, they wiggle and wobble back to their original shape.
dirty ball? All you need to do is give them a little handwashing. Be sure to use soap (hand soap seems to work best), and give the splat toy a good cleaning. Once the splat ball is dry the surface should fell nice and tacky - very tacky, actually.