הלכות טומאת צרעת

The only garments that contract impurity due to tzara'at blemishes are wool and linen garments, cloths where the warp or woof is made of wool or linen, and any leather utensil, whether hard or soft. Even leather that is colored naturally is susceptible to impurity because of blemishes. Felt is considered like garments and is susceptible to impurity because of blemishes. Tents are susceptible to impurity because of blemishes whether they are made from wool or linen or they are leather.

All garments of wool and linen are susceptible to impurity except those belonging to gentiles. When a person purchases a garment from gentiles, if tzara'at appears on it, it should be viewed as if for the first time. When a garment is made from mixed species - wool and linen - it can incur impurity because of tzara'at blemishes.

The following rules apply when camels' wool and sheep's wool were spun together: If the majority is camels' wool, it does not contract impurity because of blemishes. If the majority is sheep's wool, it does. If equal amounts are used, it can incur impurity. The same laws apply when flax and hemp are mixed together.
The wool of a sheep born from a goat does not contract impurity because of blemishes. When the warp of a garment was linen and its woof, hemp, or its warp hemp and its woof, linen, it does not contract impurity because of blemishes. Similarly, if its warp or woof was linen or wool and the remainder goat's hair or the like, it does not contract impurity because of blemishes.

A hide that was not processed does not contract impurity because of blemishes. Similarly, a hide that is an unformed mass before implements were made from it, does not contract impurity because of blemishes. This can be inferred from Leviticus 13:52 which speaks of "leather articles." Nevertheless, all leather articles - whether flat or receptacles - are susceptible to impurity because of blemishes.

The hides of sea-animals do not contract impurity because of blemishes. If anything that grows on the earth was connected to such a hide, even a strand or string of wool or flax or the hide of an animal or a beast that was processed to any degree, and an implement was made, tzara'at blemishes can cause it to contract impurity, provided it was connected to it in a manner that garments are connected with regard to impurity.

The thread for the warp and the woof - whether of wool or of linen - are susceptible to impurity because of blemishes immediately after it has been spun even though the linen has not been whitened, nor the wool soaked in hot water.
How much thread must be on a ball of thread for it to contract impurity because of blemishes? Enough to weave a cloth three fingerbreadths by three fingerbreadths from it, both the warp and the woof. This applies whether it was all warp threads or all woof threads. If the ball of thread was collected from separate threads, it is not susceptible to impurity because of blemishes.

The following law applies when a) they are two balls of thread connected to each other with a thread, b) part of the warp thread is wound over the top frame of the loom and part over the bottom frame of the loom, or c) one side of a cloak is connected to the other with one strand. If a blemish is discovered on one of these entities, the other is pure even though the strand connects them.
If a blemish is discovered in the weaving thread and in the warp that has not yet been woven, even though a portion of the blemish exists on the cloth and a portion on the warp, it is impure. If, however, the blemish appears on the unwoven warp alone, the woven cloth is pure. If the blemish appears on the woven portion alone, the unwoven warp is pure.
If a blemish appears on a wrapping blanket, the strands protruding from it should be burnt with it. If the blemish appears on the strands, the wrapping blanket is pure. If the blemish spreads from the strands to the wrapping blanket, the wrapping blanket is impure.

All utensils that are fit to contract other types of impurity - even though they are not fit to contract the impurity that results when a zav treads on them, because they are not meant to be lied upon or sat upon - are susceptible to impurity because of blemishes. To cite examples: a ship's sail, a curtain, a barber's sheet, a mantle for scrolls, a belt and laces for shoes and sandals that are a gris wide. These all contract impurity because of blemishes. Needless to say, other articles do, e.g., pillows and cushions.
A leather drinking pouch and a carrying case should be inspected in their ordinary fashion. A blemish is considered to have increased in size when it spreads from their inner side to their outer side or from their outer side to their inner side. Similar laws apply in all analogous situations with regard to all two-sided leather utensils.

When a garment that was isolated because of a blemish was dyed or sold to a gentile, it is pure. Similarly, if it became mixed with others, they are all deemed pure. If the owner cut it up and made it into small strands, each one less than three fingerbreadths by three fingerbreadths, it is pure and it is permitted to benefit from it. If one of the strands was three fingerbreadths by three fingerbreadths and the blemish was discovered on it, it alone is impure.

When a garment that had been definitively deemed impure became mixed with others, they are all considered impure and must be burned. This applies even if one is mixed with several thousands. Similarly, even if it was cut up into strands, there are all impure and it is forbidden to benefit from them.

With regard to ritual impurity, a garment or a leather utensil or threads for the warp or the woof that were isolated or deemed impure is considered a primary category of ritual impurity and is analogous to a person who contracted tzara'at in all respects. It imparts impurity when touched, when carried, when brought into a building, and imparts impurity to couches and seats on which it is placed even if they are under a stone.
What is implied? When one brings even an olive-sized portion of a garment or a leather utensil or threads for the warp or the woof that were blemished into a building that is ritually pure, everything in the building - humans and utensils - become primary derivatives of impurity. Similarly, if there is a couch or a seat located under a stone and one places an olive-sized portion on the stone, the couch or the seat becomes impure.

When a cloth is three fingerbreadths by three fingerbreadths even though it does not possess the mass of an olive-sized portion, it renders a house that was pure impure when brought inside. If it was the size of several olive-sized portions, once an olive-size portion is brought into a building that is pure, it renders it impure.
Although all the measures are halachot transmitted to Moses at Sinai there is an allusion in the Torah to the concept that an olive-sized portion of a blemished garment conveys impurity. For Leviticus 14:54-55 states: "For all blemishes of tzara'at, for a netek, for the tzara'at of garments and of houses." An association is made between blemishes affecting humans and those affecting garments and houses. Now a person afflicted by tzara'at is equated with a human corpse, as Numbers 12:12 states: "Let her not be as a corpse." Hence, just as the minimum measure for a portion of a human corpse that imparts impurity is an olive-sized portion, the minimum measure for these is an olive-sized portion.