i bought some cheapo folding crates with ventilation holes in the sides from Wilco yesterday £3 each, as I was watching a tutorial on YouTube about how to store dahlia tubers over the winter, and they recommend them as a good storage container.
You lift the tubers from the ground or out of the pots, loosening the soil around the roots, being careful not to pierce any of the fleshy parts as you'd have to throw those bits away. Shake off excess soil, hose them down and cut the stems to about 30cm from the base.
Line the crates with newspaper, put a layer of wood chippings, vermiculite or animal bedding on the bottom then lay each tuber in the crate being careful they don't touch each other, put another layer of wood chippings etc until they are covered over.
Put the lid on to stop mice being attracted to them and store them in a cool, dark place eg a cellar, garage or shed. Check them every month over the winter. If the weather gets really cold I.e. below freezing move them indoors, and keep them in a cold spare bedroom until the weather returns to above freezing,