I just switched from aspen to INDENTED KRAFT PAPER. I've read all the threads and I know that aspen is well liked but I just spent $3,000 on my man-made snakes and had to pull out a lot of aspen from the mouth of one of them. I can not afford to take the risk just because "in nature they eat a lot of debri". These snakes are not from nature, they have been born in captivity for many generations and their natural habitat is that which we provide for them and not nature. I used unprinted newspaper under indented kraft paper for twenty years and recently switched to aspen. This switch got me real worried by the amount of aspen the snakes eat with their meals. I switched back to INDENTED KRAFT PAPER it is the best substrate for your unnatural man-made babies.