I'm not sure what you mean by recycled mooncakes; perhaps you’re referring to buying and eating them after the festival has ended.
Recycled mooncake refers to the practice where bakery shops handle leftover unsold mooncakes after the festival. Instead of discarding them, the shop owners "recycle" the mooncakes. Workers remove the skin and dispose of it, while salvaging the red bean or tau sa paste filling. This recovered paste is then repurposed to create new pastries, such as tau sa piah or red bean pastries, which are sold as "fresh" products.