Well I don't know about the Spotlite PUL specifically, but I know with cloth nappies that use PUL you're not meant to put them in the dryer because it can deteriorate quickly. Might not be as important for bibs as for nappies, but they will last a lot longer if they don't go in the dryer! Plus bibs dry quickly, maybe you could suggest she just hangs them up somewhere, even on a coathanger overnight and they should be dry by morning