When it comes to packing litter, you should not use a single piece of material for all your boxes and instead use multiple layers.
You can also stack them in different ways to create different types of litter.
Litter box and bin make use of a single layer.
Lining the box and bins can help reduce the number of pieces of litter that end up in the bins.
Lacking this layer, it is best to stack them on top of each other and use a plastic bag to cover them.
To add to the litter, add a couple of bags of lint or other fibers to the corners and top corners of the box or bin.
A large amount of the litter is recycled.
The same principle can be applied to the bins too.
The more layers of litter you have, the more litter you will have to dispose of.