I found this photo on the ARS website and to me this looks like a cotton towel for substrate? I just ordered some ReptiZorb liners to try them out, I didn't get them in yet but I did find a post of someone who was taking the used ReptiZorb liners, spraying them with disinfectant and washing them in the clothes washer machine to reuse them. If that works I could really save some money, but even better if you could use a plan ol towel and just do a load of laundry to clean up! And this ball python looks really comfortable on this towel too!