If you see oil being given out in the temple courtyard for the Kohanim (priests) to eat, you do not have to ask what korban (offering) it is from; rather, you can assume that it is either the leftover oil from a wafer or the leftover oil from the log brought by the Metzorah. These are the two oils that would be given out to the Kohanim in the courtyard of the Beit HaMikdash (temple).
Many different types of menachot (meal offerings) are brought. They all have not only flour, but oil as well. But most of the time, the oil is baked into or fried into the flour, the dough, and they do not see any oil at all afterward. The one exception is the wafer menachah, where some of the oil is mixed in with the wafer, but the rest of the oil is given on the side to the Kohen to eat. But this is true of this type of menachah only if it was donated by somebody who is not a Kohen. A Kohen's menachah and its oil are not eaten, but are burned on the Mizbeach (altar). Rabbi Shimon follows the opinion elsewhere that some of the oil is smeared on the wafer offering, but the rest is given to the Kohanim to eat. The Chachamim (Sages), though, hold that all the menachah is smeared on the wafer menachah. So, in the introduction that we gave before, we said that the wafer menachah does not have all the oil mixed in. That is only according to the opinion of Rabbi Shimon. According to the Chachamim, there is no menachah that has any leftover oil that is eaten by the Kohanim.
In addition to the regular animal offerings that the Metzorah, the man with leprosy, who is trying to become pure, has to bring, he also brings a log, which is a measurement of oil. The Kohen takes some of the oil and sprinkles it toward the Kodesh HaKodashim (Holy of Holies). Then he puts some of the oil on the right ear, thumb, and toe of the Metzorah, and the leftover oil, the rest of that oil, is given to the Kohanim to eat. So if you see this oil, if you see oil being given out in the courtyard of the Beit HaMikdash to the Kohanim, it must be from one of these two korbanot.
If you see the oil that is given to the menachah, if you see oil being put on the fires of the Mizbeach, you do not have to ask what offering it was from; rather, it is either the leftover oil from the wafer menachah offering brought by the Kohanim, or the leftover oil from the daily menachah offering of the Kohen Gadol, the anointed Kohen. And as we mentioned earlier, according to Rabbi Shimon, the wafer menachah has leftover oil. But if it is brought by a Kohen, the leftover oil, like any menachah brought by a Kohen, is not eaten but is burned on the Mizbeach—the whole thing. So we are saying that here as well. If there is leftover oil being burned on the Mizbeach, you can assume that it is from the menachot of the Kohanim or from the Minchat Kohen HaMashiach (the anointed priest's meal offering).
The Torah tells us that the Kohen Gadol—specifically, it talks about Aharon—has to bring a menachah offering every day. Half of it has to be brought in the morning, and half in the afternoon. It tells us that a very large amount of oil is brought, and because it is baked before it is fried with the oil, not much of the oil is absorbed into it. So there is a lot of oil that remains on its own. That oil is burned on the Mizbeach, like any other menachah of the Kohen. So, since these are the only oils that are burned on the Mizbeach, we can assume that it is one of these two, because oil is not allowed to be donated as a voluntary offering to the Beit HaMikdash. Rabbi Tarfon says you could make a voluntary offering of oil, which is then brought and burned on the Mizbeach. So according to Rabbi Tarfon, if we see oil being burned on the Mizbeach, there is also a possibility that it is oil from a person who voluntarily donated it to the Beit HaMikdash.