Generally speaking I do not think anyone really does since we are printing on vinyl that is intended to be printed on. On the occasion that we are going to print on something different like a solid color vinyl we wipe it down with isopropyl alcohol. Even that has limitations though - say we need to print a half a roll of metallic silver vinyl.... we are not going to unroll 25 yards of vinyl to wipe it down, we are just going to go with it. I can say that we have done this many many times though and have really never had much of any issue. The catch of course is that vinyl not specifically intended for print is not guaranteed to be free of any surface contamination that might affect printing. Vinyl that is specifically manufactured just for printing should be free of any sort of surface contamination already.
Edit to add - yep just noticed this is in the Edge section. Same as Fred below.... I've never cleaned vinyl we use on our Edge other than making sure there is no dust on the first foot that might have been exposed while the roll sits on the racks.