I personally can't stand Aspen, especially for BPs and other species which have higher humidity requirements. It's messy, doesn't hold humidity, molds, etc...and I don't like how it looks at all.
I only use it for my hognose since they require low humidity. He's able to burrow and it holds his tunnels.
I personally wouldn't bother cleaning the enclosure until I could put Eco Earth and ReptiBark in the enclosure.
Just curious...do you live somewhere that makes it hard for you to get substrate?
I have a deposit on a Rosy Boa, they too require low humidity and burrow, have you ever used paper towels? If you have, why do you choose aspen over paper towels?