Kelim, Chapter Twenty-Four, Mishnah Nine
There are three different types of baskets:
1) The one for dung is susceptible to midras uncleanness;
2) The one for straw is susceptible to corpse uncleanness;
3) And a camel’s rope bag is free from all uncleanness.
Section one: The basket used to take dung out to the fields to be used as fertilizer is susceptible to midras impurity because it can be sat upon.
Section two: The type of basket used for straw is not sat upon, so it is not susceptible to midras. But it is a vessel, therefore it is susceptible to corpse uncleanness.
Section three: The rope bag put onto a camel has holes in it that are large enough to let out pomegranates. Therefore, it is not susceptible to impurity.