Ok this is going to sound strange to everyone I'm sure. but does aspen have ANY smell to it at all specifically if it gets wet or old. I have really really really week lungs, as well as allergies to any non reptilian pet you could name. I had a pet bird who recently died. if his cage wasnt cleaned every 3-4 days I'd start to sneeze and weeze when playing with him. And if he wasn't cleaned by about 7-10 days I'd start to have some real problems. Another thing that sets it off is saw dust, wood chips, and strong musty smells. I'd like to use aspen for BP but I don't want to have to deal with not being able to breath every time I clean its cage.