Yes dirt from outside or a mix of sand and hummus with all the bacteria that can break down waste and allow natural looking cages.

The first book I read about it was "Venomous snakes' by Ludwig Trutanu.

And "the art of keeping snakes' by Philippe de Vosjoli. Was really good and interesting.

I am going to give it a shot but I really want to hear some more first hand experiences.

I am also worried about impaction and infection in the cloaca.