Dust-cover material

This is a dumb one, but: There used to be commercially available dust covers made out of translucent plastic (vinyl???) that fit over terminals, monitors, printers etc. (and I think there was a full line of custom-fit ones for ham rigs too). It seemed silly at the time but now that I'm chest-deep in old computers/terminals/ peripherals, some of the stuff goes many years between uses and the dust is a real problem. So ... I have a sewing machine (yes older than my computers and come to think of it, it gets dusty too) and more patience than I deserve, but I can't find a source for the kind of plastic sheeting I mean. Hardware-store drop cloths are too flimsy (might as well just use a trash bag) and I've gotten nowhere googling, but maybe that's just because I don't know the correct name. Anyone know what I'm talking about, and where to get it by the yard etc.? Thanks! John Wilson D Bit