Thanks cat - might try the strip wash and sun (what's that? ) I suspect the reason they smell is cause I've been drying them inside lately and not out in the fresh air and the same ones seem to get used rather than rotating through them as we're only using them for day naps with ds1 or if he's decided not to tell us (or go by himself) when he needs to go to the toilet at home - he can use toilet appropriately when out but not at home