is purified by rubbing. Thus, if a mirror becomes impure and you rub it until it is clear and no trace of filth remains on it, it becomes pure.
The second category is that from which impurity cannot be removed by rubbing because it is rough. Such an object is not purified by rubbing, because particles of the impurity remain within it (1).
His statement, “Nor by transformation,” means that it changes—that is, it changes from one state to another.
This means that impurity is not purified through transformation, because its very substance remains.
An example is the dung of a donkey used as fuel until it becomes ashes: it does not become pure, because this is the very substance of the impurity. It has already been mentioned that inherent impurity can never become pure (2). According to the apparent meaning of the author’s words, the smoke rising from this impurity is also impure, because it is produced from that impurity. Thus, if a person’s garment or body is soiled by the smoke while it is moist, it must be washed.
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Another example: if a dog falls into a salt flat—land containing salt—and is transformed into salt, it does not become pure; moreover, its impurity is severe.
They make the following exceptions:
- Wine that turns into vinegar on its own (3).
- A blood clot that develops into a pure animal.
The correct view is that there is no need for this exception, because, according to the preponderant opinion, wine is not impure, as will follow (4).