The phrase "walnut shells" refers to the hard outer covering of walnuts, often used in different applications such as crafts, gardening, or even as an exfoliant in beauty products. Full definition
Rabbit food — which is mostly ground hay and makes an excellent low - cost litter for small rodents — rates high on absorption, while ground walnut shells would rate at the bottom. (petbusiness.com)
I even changed to an all - natural, clay - free cat litter made from walnut shells. (1800petmeds.com)
I know of one store that tends to put all its stock on crushed walnut shells, and while the shells are attractive, I think this bedding is too sharp if accidentally ingested. (petbusiness.com)