there aren't any 'rules' as such.....its recommended that you dont place PUL in the dryer all the time or elastic as it can deteriate quiet quickly.

FWIW....I place boosters in the dryer in winter...l have no choice really and they are still as aborbent as normal
yeah, i know, it was just the easiest way to get it across ><;

All my inserts, boosters went in the wash...left the shells out under my patio to hoipefully dry in the wind. Jack is sposies today. humph. that'll learn me for being lazy and not getting the clothes off the line and leaving them overnight.