Commentary for Bava Metzia 3:8
יוֹצִיא לוֹ שְׁתוּת לְיַיִן. רַבִּי יְהוּדָה אוֹמֵר, חֹמֶשׁ. יוֹצִיא לוֹ שְׁלשֶׁת לֻגִּין שֶׁמֶן לְמֵאָה, לֹג וּמֶחֱצָה שְׁמָרִים, לֹג וּמֶחֱצָה בָּלַע. אִם הָיָה שֶׁמֶן מְזֻקָּק, אֵינוֹ מוֹצִיא לוֹ שְׁמָרִים. אִם הָיוּ קַנְקַנִּים יְשָׁנִים, אֵינוֹ מוֹצִיא לוֹ בָּלַע. רַבִּי יְהוּדָה אוֹמֵר, אַף הַמּוֹכֵר שֶׁמֶן מְזֻקָּק לַחֲבֵרוֹ כָּל יְמוֹת הַשָּׁנָה, הֲרֵי זֶה מְקַבֵּל עָלָיו לֹג וּמֶחֱצָה שְׁמָרִים לְמֵאָה:
He deducts a sixth for wine [if he deposited wine with him, and it got mixed up with his wine. (The vessels absorb a sixth.)] R. Yehudah says: A fifth. [For the earth from which the vessels were made in the locale of R. Yehudah absorbed a fifth; all according to the locale.] He deducts three logs of oil to a hundred — a log and a half for lees; a log and a half for absorption. If it were refined oil, he does not deduct for lees. If they were old vessels, he does not deduct for absorption. R. Yehudah says: Also if one sells refined oil to his neighbor all the days of the year, he (the buyer) accepts (a deduction of) one and a half to a hundred for lees. [Just as they stipulated (a deduction for) lees for the depositor, so they stipulated it for the seller, viz.: If one sells oil to his neighbor and gives him from his jugs refined oil which he constantly uses, the buyer accepts a deduction of a log and a half to each hundred for lees. The halachah is not in accordance with R. Yehudah.]
Bartenura on Mishnah Bava Metzia
English Explanation of Mishnah Bava Metzia
He may exact of him three logs in every one hundred logs of oil one log and a half for sediment and one log and a half for absorption. If the oil was refined he may not exact for sediment. If the jars were old he may not exact for absorption.
Rabbi Judah says: “Also if a man sells to his fellow through the year, the buyer must undertake to accept a reduction of one and a half logs because of sediment.
With wine and oil there are no reductions for mice, as there were with produce, but there are reductions due to sediment and absorption in the sides of the clay vessels which were used at the time. With wine the guardian may exact a reduction of one-sixth or one-fifth according to Rabbi Judah.
With regards to oil it depends on the type of jar and the type of oil. Regular oil is reduced 1½ per cent due to sediment, but refined oil does not produce any sediment and therefore reductions may not be exacted. Regulars jars absorb 1½ per cent but old jars, whose sides are more hardened and have already absorbed oil, do not absorb any oil. Therefore if the jars were old the guardian may not exact a reduction for absorption.
Rabbi Judah adds that not only may a guardian exact a reduction of 1½ per cent the oil returned to the owner, but so too may a person who sells refined oil. In other words if Reuven tells Shimon that he is selling him 100 logs of oil and then gives him refined oil, he only need give him 98 ½ logs since 1½ logs of regular oil would be worthless sediment anyway.