Midrash su Levitico 13:47

1) (Vayikra 13:47) ("And the garment, if there be in it a plague-spot of leprosy, in a garment of wool or in a garment of flax,") "And the garment": I might think (that this includes) remnants and cardings and coarse silk and cotton and camel wool and rabbit wool and goat down; it is, therefore, written "in a garment of wool or in a garment of flax.

2) This tells me of garments completely of wool or completely of flax. Whence do we derive for inclusion intermixtures? From "And the garment." This tells me only of one of the varieties that is partially intermixed. Whence do I derive for inclusion one of the varieties that is totally intermixed or intermixtures that are totally or partially interwoven? From "And the garment." This tells me only of a garment (the size of) three by three (fingers). Whence do I derive a garment lacking three by three? From "And the garment." This tells me only (of a plague-spot) which has room to spread (see Vayikra 13:51). Whence do I derive (a plague-spot) which does not have room to spread? From "And the garment." These are the words of R. Eliezer. R. Yishmael said to him: "You tell me to write! Wait until I can assimilate (all that you have said)!" R. Eliezer retorted: "Yishmael, you are a mountain-palm!" (much too rash).

3) I might think that they are subject to tumah whether dyed or not dyed; it is, therefore, written: "in a garment of wool or in a garment of flax" — Just as flax is in its original state (i.e., it is not the practice to dye flax, so, (for plague-spot uncleanliness we require) wool in its original state.