1:
Our present mishnah continues the topic that was broached towards the end of mishnah 7: the Asherah. This time we are concerned not with the tree itself but with uses to which people may but its wood.

2:
We have mentioned on several occasions that a Jew is forbidden to derive any benefit whatsoever from anything connected with idolatry. Our present mishnah indicates the extent to which that prohibition must be taken.

3:
Let's say that a tree which was previously used as an Asherah by non-Jews was abandoned by them. A Jew might want to avail himself of this tree in some way, by chopping it down and using its wood; or even just lopping off a branch here and there for some purpose or other. It is immaterial whether the tree belongs to someone or is ownerless: the prohibition stands because of its prior function.

4:
One use to which the wood of trees was put was in order to heat ovens of various kinds. Our mishnah distinguishes two kinds of oven in this regard. The first clause of our mishnah says that if a Jew uses wood taken from an Asherah-tree to serve as fuel for his oven he has created a problem for himself. If the oven is new - that is to say that if this is the first time that it is being fired - the oven must be completely dismantled! This is not as problematic as it sounds to us since ovens and ranges in Talmudic times were quite simple. They consisted of a shelter made of clay; the fire was lit inside the shelter which had a hole in its top on which pots could be stood for cooking. The only practical difference between an oven and a range was that the oven could heat only one pot at a time while a range could heat two (or perhaps more, depending on the size of the range). The reason why a new oven must be dismantled is because the first firing benefits the material from which it is made and improves it.

5:
If the oven was old - that is, if it had already been used previously - it need not be dismantled. It must be allowed to cool. Then it may be reheated with wood that is permitted and used as usual.

6:
But what of a loaf (for example) that had been cooked on this oven? It is forbidden to derive any benefit from such a loaf: obviously, it may not be eaten; but it may not even be sold to a non-Jew. Furthermore, if such a loaf got mixed up with other loaves which had not been baked on this oven and if it is now impossible to identify the forbidden loaf among the others they must all be abandoned as prohibited.

7:
Rabbi Eli'ezer, contrary to his usual conservatism, would seek here a leniency. His argument is presumably based on the prohibition to waste good food [bal tashĥit]. He suggests that the food be sold to a non-Jew; the profit from the sale should be thrown into the Dead Sea - or, in other words, destroyed. The rest of the sages reject the idea out of hand, so great is the horror of deriving any benefit whatsoever from the appurtenances of idolatry.

8:
Another typical use of wood was to make a shaft for a loom. Our mishnah explains that if the shaft came from an Asherah-tree it is not only prohibited in itself but also any cloth woven on that loom is prohibited. Furthermore, if such cloth becomes mixed up with other cloths (and if they become mixed up with other bales further down the line) they are all forbidden if the offending cloth cannot be identified. Here too Rabbi Eli'ezer would suggest a leniency but the sages are adamant: there is no way to 'redeem' anything that derives from idolatry.

9:
However, despite our mishnah, there were some authorities in the middle ages who did approve the leniency of Rabbi Eli'ezer.

Raphael Kanter writes concerning mishnah 6 of this chapter:

Is it possible that what the mishnah says is that if there is a wall the Jew builds two cubits away from the wall and the temple is built two cubits away from the wall???? The phrase mechtzah al mechtzah is what I don't understand.

I respond:

You will recall that the mishnah [AZ 043] is discussing a situation in which a building belonging to a Jew has one wall in common with a pagan temple. If the wall collapses (as often happened in Talmudic times because in most cases the walls were simple stones piled on each other) the Jew must rebuild his wall at a distance from the pagan temple of at least four cubits. The phrase which Raphael finds problematic, meĥtzah al meĥtzah in Hebrew, means that the Jew and the non-Jews must go halves. In the first example the wall belongs to one side or the other and the other has just used it for their purposes instead of building their own wall. However, in the phrase which we are now discussing the wall originally belonged to both parties in common. So, from where must the Jew measure his four cubits? The answer of the mishnah is that he must measure from the middle point of the horizontal of the wall as it originally was, as if the nearest half of that wall was his.