I just received he Material to build my Screen. I am using the Blackout Cloth. The problem is that it was folded. I am going to be making a portable screen with a Collapsible frame, so I am wanting to know how to get the wrinkles out of the cloth? I am trying to stretch out the wrinkles but when I release the tension the wrinkles return. Any IDeas?? Can I steam them out? a warm Iron?