Diy projector?

Over the past few weeks i have been making a fresnel lens projector out of a cardboard box with a fresnel lens. i get the picture really big on the ceiling and i can focus it but it dosent become clear to be watchable should i build this again using wood so not as much light escapes or is there a way to fix the problem without building it out of wood.
Answer
Try rapping it with foil, if it gets better well nice