Masking Splatter with Mr Hobby masking paint. Pour some masking paint into a cup. Added a bit of water to dilute masking paint. Cut polycarbonate cowl according to your car. Use a normal paint brush and splash the masking paint on the underside of the polycarbonate cowl. Let the masking paint dry. For thinner lines on cowl, masking paint should not be too diluted. After masking paint is dry. Spray paint on cowl of any colour of your choice. Let it dry then using a toothpick to peel off masking paint. Do some clean up to remove any excess masking paint. Finally spray a different colour paint on cowl.