Kelim, Chapter Eight, Mishnah Two
1) If the hive was complete, and so too in the case of a basket or a skin-bottle, and a sheretz was within it the oven remains clean.
2) If the sheretz was in the oven, any food in the hive remain clean.
3) If a hole was made in it:
a) A vessel that is used for food must have a hole large enough for olives to fall through,
b) If it is used for liquids the hole must be large enough for liquids to pass into it,
c) And if it is used for either it is subjected to the greater restriction: the hole need only be large enough for liquids to pass into it.
Section one: If the hive-vessel had not been broken, or alternatively the vessel placed into the oven was an unbroken basket or skin-bottle, the sheretz in the vessel does not defile the oven. Since this is a complete vessel it works as a barrier to keep the impurity away from oven.
Section two: Similarly, if the sheretz was in the oven, the hive-vessel protects the food within it from becoming impure.
Section three: If one of these vessels was perforated with a large enough hole, it no longer counts as a vessel and therefore will not prevent impurity from going from the oven to the inside of the vessel and vice versa.
The mishnah now repeats that which we learned in 3:1. The vessel is “annulled” from being considered a vessel if the hole is large enough to let out that which it normally holds. So if it normally holds food, if the hole is large enough to let olives fall through, it is no longer a vessel. If it holds liquids, it must be large enough to let liquids out. If it is used for both liquids and solids then we go by the stricter measureif the hole is large enough to let even liquids out, it is not a vessel and it does not serve as a barrier to impurity.