1:
Our mishnah is concerned with the status of various foods if they become mixed with yeyn nesekh.

2:
The first clause of our mishnah is simple. If yeyn nesekh falls on grapes they may be rinsed in cold water and then they may be eaten because the water removes from the grapes all the wine. However, if the grapes were split open rinsing them with water will not avail because the wine will seep into the fruit.

3:
The next clause is concerned with an actual case. A merchant, one Beothos ben-Zonin, was importing dried figs by ship. During the passage a cask of wine, which was yeyn nesekh from the Jewish point of view, broke open and the wine spilled upon the figs. When asked whether Jews could buy those figs the sages responded that it was permissible. Their reasoning is explained in the next clause.

4:
Our mishnah now brings a general rule. If any foodstuff or liquid that is prohibited mixes with some other foodstuff or liquid that is in itself permitted the resultant mixture is permitted or prohibited according to this general rule: if the prohibited foodstuff or liquid improves the taste or flavour of the foodstuff or liquid with which it has become mixed the whole mixture is prohibited; however, if the mixture spoils the flavour then it is permitted - because no benefit is being derived.

5:
The above rule is true, of course, only when the prohibited foodstuffs or liquids are permitted in themselves, but for some 'technical' reason have become prohibited; if they are intrinsically prohibited the rule does not apply. In our case, wine is a permitted beverage; it is only prohibited if it belongs to a non-Jew or had been handled by a non-Jew. Apparently, wine spoils the flavour of dried figs so the figs are permitted.

6:
The last clause of our mishnah is, in fact, just an illustration of what we have just explained. If vinegar derived from yeyn nesekh becomes mixed with groats or grits - crushed grains - they are permitted because the vinegar spoils the taste of the groats.

In AZ 063 we learned that a Jew might have to forego his wages if the work involved something that is religiously forbidden. Mark Lehrman writes:

It seems to me that if the rules regarding forfeiture of payment were widely known to non-Jewish employers, an unscrupulous employer could intentionally "game the system" and cause an innocent Jewish laborer significant financial hardship. The only certain way to avoid this would be for a Jew to reject employment from a non-Jew. Was this an intended consequence?

I respond:

I would imagine that many non-Jews were aware of this ruling. I would also imagine that there were many honest non-Jews who refrained from taking advantage of the ruling. However, I am sure that Mark is right in suggesting that there must have been non-Jewish employers who would take advantage of this ruling. We must assume that Jewish labourers would try to work only for honest non-Jewish employers. One untoward incident would be enough to warn off all Jewish labourers from an unscrupulous employer. And remember that wages were paid on a daily basis. (If an honest employer erred in ignorance he might be able to make it good for his Jewish employee by later offering him the forfeited money as a gift.) However, it seems to me that the simplest answer to the problem of a Jewish labourer who was required to forfeit his wage was for him to accept payment from the non-Jew and then dispose of it in a manner that would not benefit him in any way. In AZ 039 we saw an example of one such method.

Mark is right that "the only certain way to avoid this [kind of situation] would be for a Jew to reject employment from a non-Jew". However, the very fact that our mishnah raises the possibility would suggest that many Jews did work for non-Jewish employers. I cannot recall any other source which would suggest that the sages had the deliberate intention of discouraging Jews from working for non-Jews.

I take this opportunity of wishing everybody a very happy Shavu'ot (Pentecost). Ĥag Same'aĥ!