Jazzmyn,
It is a really good idea to post a note stating that there are nut shells in the pin cushions. When I use them in pin cushions as gifts, I always let the person know. My husband uses nut shells for sand blasting metal parts and I think
they are just cleaned, then ground to certain sizes (fine,course, etc.). There are no additives in the bags of shells at the pet store for use in the lizard cages.
Brenda