I was in the same boat and gave up on the aspen. It's great for spot cleaning but it's hard to keep it entirely clean as you can't always tell where it's been soiled. You could try mixing it with cypress...go easy on the cypress if you do, as that will absolutely hold the moisture! I was having to mist twice a day when I had mine on aspen...not a huge deal but with 10+ snakes, it got a little tedious day and night. I gave up after about six months of fighting it to keep the humidity up where it should be and that was in a XPVC rack and tub setup. I use paper towels. They're cheap, they can be recycled and it's easy as pie to tell when they're dirty. My two cents.
it's good to know that I am not alone. I thought about switching and probably will. I just ran out of aspen so this might be the time to do it. Thanks