Substrate

The primary purpose of an absorbent substratum beneath your snake is to absorb feces and spilled water.  By desiccating moisture, the resulting dry substrate medium controls odors and promotes a germ-free environment for your snake.
In the realm of substrate materials, remember the three Don’ts.

Don’t use CEDAR
Don’t use ANY KIND OF BARK
Don’t use SAND or GRAVEL.

Cedar shavings and pine (or fir) bark products are toxic to snakes and are therefore not recommended. 
Reasons why sand and gravel are inherently dangerous to your snake include: 
o They are non-absorbent, thereby allowing the growth of bacteria that can cause offensive odors and disease.
o  If ingested, indigestible sand and gravel pass through the digestive tract of snakes, and can cause internal injuries and impaction.
o  Not only can such non-organic substrates cause intestinal impactions in your pet, but sand and gravel are excessively abrasive to your snake’s skin and eyes.  In so much that corns are inherently nocturnal, when they have temperature options, they choose those temperate zones that afford them darkness and seclusion.  Hence, burrowing is often a life-saving option for them, but if they reason that their only escape from light and inappropriate temperatures is to dig, they can damage themselves burrowing through rock and gravel.
Secondary to the desiccating function of absorbent substrate materials is that of buffering your snake from temperature extremes.  In Nature, it’s difficult to find better insulating material that is more efficient than wood pulp. 

Folded newspaper – while not aesthetic – is sanitary, inexpensive, and convenient, but many layers are necessary to create a safe barrier between the snake and the heat source (UT or OT). 

Shredded newsprint does not form a solid substratum, and therefore is not recommended. While not known to be a medical threat to reptiles, the ink on newsprint will transfer to and adhere to your snake, making it gradually darker in overall coloration until its next shed.
 
Aspen pulp bedding (available in most pet stores) is a naturally absorbent hardwood substrate that most breeders and keepers use for its relative neutral smell and reduced resin content.

Pine and fir pulp shavings which contain higher levels of oils and resins are potentially more toxic and should only be used for adult corns – in well-ventilated cages.

Intoxication at harmful levels has been reported in cases where snakes co-incidentally ingested pine or fir wood particles. In addition to the potential for casual (and usually unintentional) ingestion, these relatively harmful bedding particles are consumed during feeding and even pose a risk of toxically polluting the snake’s drinking water.

Avoid using bark forms of pine and fir as they are the parts of trees with the highest resin concentrations and have been known to be harmful to snakes.  In addition to contributing to snake deaths resulting from ingestion of bark pieces (often only surgically removable) constant bodily contact with bark can result in the slow-dose intake of toxins into your snake’s bloodstream via absorption through their skin.
Aspen is the most popular substrate used by snake keepers that want to display their pets on attractive bedding that offers the lowest risk of injury and intoxication while providing superior desiccating and insulating protection. The particulate shapes of most aspen bedding products make spot cleaning a breeze, while a total replacement is often necessary only a few times annually.

We recommend the shredded aspen, VS., the flake. The strand-like shape of shredded aspen creates a natural matrix by laying in lattice fashion. As a snake burrows through shredded aspen substrate, most of their tunnels actually stay in place, for easier navigation.

Let your eyes and nose dictate the frequency of substrate maintenance. Many pet stores also offer recycled newspaper products made for cage substrates that are sanitary and absorbent and make excellent cage floor coverings. 

We do not recommend the use of cage “carpeting”, as it is not absorbent – thereby promoting bacterial growth that results in odor.  And many “carpet” layers would be required to create a safe temperature buffer between your snakes and UT heating devices.