I kinda do what Mike said but it's a grate out front!! From what I understand it's harmless but I have been wrong about these things before. I also dye a bunch of APC props for the plane I dyed the canopy for if the dye is a dark color. I have had a bunch of people try to buy my custom made props at fly in's before until I told them the trick. The stories about how I have these props special made are priceless!!