Masechet Avodah Zarah, Perek Heh (Chapter Five), Mishnah Yud Aleph. In the times of the Mishnah, the wine press was sealed with a little bit of tar on the wall. Tar has a very strong smell, and that could destroy the entire flavor of the wine. So, after they put on that coating of tar, they would rub a small amount of wine on it, and it would reduce the effect of the tar. It would sort of flavor the tar so it wouldn't give off such a negative smell. That would create a problem when an idol worshiper was the one who coated the wine press, because then he took wine and made that wine Yayin Nesech (wine), and then he used it to smear onto the tar. Now you're gaining benefit from that Yayin Nesech because you're using the wine press. So here we'll talk about what has to be done in such a case in order to make the wine press usable.
Gat shel even she-zaf'tah oved kochavim menagbah. The wine press was coated by an idol worshiper with tar. We have to assume that he rubbed Yayin Nesech wine onto the wine press. Menagbah v'hi tehorah. The Jew is allowed to wash and dry off the wine press, and it's considered to be cleansed of all non-kosher wine. That's all that has to be done over here. The wine press is usually made of stone, and therefore the stone wouldn't absorb the wine into the tar in such a strong way. So, to remove the wine from that tar, from the coating, all that has to be done is wash it and dry it. But if the wine press was made from wood, Rabbi says you should wash and dry it to cleanse it, the same as the stone wine press, because the wooden walls also would not absorb the wine. Remove the tar, and then wash and dry the surface of the wine press. When you're dealing with wood, a lot more tar is needed to coat the wine press in order to make sure that the wine press is clean. So, remove the tar, then wash and dry the surface of the wine press, and make sure that the wine press acts and functions properly. Therefore, the fact that you have much more coating over here, much more tar, means it'll absorb a lot more wine. And then it's simply not something you could just wash off and take care of, because there's probably a lot more wine absorbed into that tar. So even though wood also doesn't absorb in the same way that stone wouldn't, here they have to actually rip off the coating and then wash and dry it in order to completely clean it out.
But if the wine press was made of earthenware, even if he removed the coating of tar, the wine press would still be prohibited. Earthenware absorbs in the highest possible manner. So therefore, we assume that forbidden wine was absorbed not simply only into the tar, the coating, but also into the walls of the earthenware wine press as well. So therefore, it's prohibited to use, even after the tar is removed. After the tar was removed...