rear projection screen questions

[mjz55]

I just got a 10' rear projection screen and frame for free. I never seen one and I wonder about this one. It has a green tint, is this normal? How do you clean these?

[bluntfaktory]

rear projection screen arn't white they're usually gray . it's so you only get the illuminated image and not the projector beam lines , it's like a white screen would be too transparent .