according to the instructions im only supposed to put them in for 2 mins but when i took them out it didnt seem like enough, however the instructions also say that if you dont follow the wattge instructions it could damage the microwave...5 mins really doesnt seem to long to me though, its like as long as it takes to defrost something, and they seemed to be better cleaned after 5 mins, i could try 4 mins...which is reccommended for 100 watts lower than my microwave, i dont know, im just thinking out loud