Just looking at them on allergy best buys. Anyone got one and what are they like? Bit baffled at how good they are and cant see a good enough picture of it to really know what its like. I presume it sticks over just the opening not the whole window and so to open and shut window you may have to keep messing around with it. Is it washable to get the pollens off the outside else they may get flapped around in the process?