Yeah I wouldnt do that. I keep my inside enclosures around 70-80% and aspen would mold very quickly. I wouldnt use hay for bedding for the same reason. Im sure both of those things have caused plenty of eye problems because of how dry they are. Cypress mulch is perfectly fine all by itself. If you are looking to mix two things together go with a coco coir and cypress mulch mix. Sphagnum peat moss mixed with cypress mulch is also a great option.