Stacking cast iron pans without putting a layer of protection between each pan can damage them in multiple ways. That layer can be a paper towel, newspaper, or a spacer, like cork.

Cast iron is a heavy material, so the surface of your skillets can get scratched or scraped when stacked without protection. That, in turn, can damage the seasoning of your pans.

Protective layers also keep the pans’ surfaces clean by preventing contact with the dirty bottoms of other pans. Plus, they keep sticky, over-seasoned pans from sticking together.

Lastly, during long-term storage, the paper towel can soak up any moisture left behind in the microscopic crevices of your cast iron pans and thus prevent rust from forming.