Ohalos 4:2-3

Ohalos 4:2

If a drawer of a cupboard had an opening of one handbreadth but its outlet is not a handbreadth, then if there’s something ritually impure inside the drawer, the house is rendered unclean but if there’s something ritually impure in the house, the contents of the drawer remain clean because the nature of ritual impurity is to exit and not to enter. Rabbi Yosi declares the house to be ritually clean because the impure contents of the drawer could be removed in half measures or burned where they are.

Ohalos 4:3

Let’s say that a cupboard stood in a doorway and opened outward. If there’s something ritually impure inside it, the house remains clean but if there’s something ritually impure in the house, the contents of the cupboard are rendered unclean because the nature of ritual impurity is to exit and not to enter. If the cupboard’s wheel protruded three fingerbreadths behind it into the house and there was something ritually impure in the wheel under the rafters, the house remains clean. This is only the case when there is a space of one handbreadth in the wheel, it is not detachable and the cupboard is of the requisite size (i.e., at least 40 seah).