Gemara

Whenever Ravina and Rav Acha argue, the Halachah follows the lenient opinion.

Shabbos 44a (Beraisa - R. Yehudah): One may move a new Ner, but not a used Ner;

R. Meir permits moving any Ner, except for one that was burning on Shabbos. (It is Muktzeh Machmas Isur. It was Asur to move it while it burned, so it is forbidden for all of Shabbos).

46a (Rav Yehudah): One may move an oil lamp, but not a kerosene lamp. (It smells terrible. People do not use it for anything else);

(Rabah and Rav Yosef): One may move even a kerosene lamp.

Question (Rava): Why do Rabah and Rav Yosef permit moving a kerosene lamp?

Answer (Rav Avya): It may be used to cover a Kli.

Question (Rava): If so, it should be permitted to move rocks in the Chatzer. They may be used to cover Kelim!

Answer (Rav Avya): We are more lenient about a kerosene lamp, because it is a Kli!

128a: Rav forbids eating Muktzeh like R. Yehudah, but he permits moving it like R. Shimon.

140b (R. Chiya bar Ashi): One may move salted meat hanging to dry, but not salted fish.

153a (Mishnah): When one's donkey reaches the outer gate [of the city], he unties the ropes [holding up sacks with Muktzeh], and the sacks fall by themselves.

154b (Rav Huna): If it was carrying glass Kelim, he puts pillows and blankets underneath before untying the ropes to make the sacks fall.

He refers to bloodletters' Kelim, which may not be moved on Shabbos.

156b (Mishnah): We may cut gourds in front of animals, and a carcass in front of dogs;

R. Yehudah says, if it was not dead when Shabbos began, we may not cut it, since it was not prepared.

We find that Rav holds like R. Yehudah;

(Rav): Double-mats used to cover merchandise are forbidden [on Shabbos];

(Shmuel): They are permitted.

157a (Rav Acha or Ravina): For all laws of Shabbos, the Halachah follows R. Shimon, except for Muktzeh Machmas Mi'us (something that disgusts a person), e.g. a used Ner (lamp);

(The other of Rav Acha and Ravina): The Halachah follows R. Shimon even regarding Muktzeh Machmas Mi'us, but not regarding Muktzeh due to Isur, e.g. a Ner in which a fire was burning at the start of Shabbos.

Rishonim

Rif and Rosh (Shabbos 21a and 3:20): The Halachah always follows the more lenient of Rav Acha and Ravina. Therefore we permit Muktzeh Machmas Mi'us, but not Muktzeh due to Isur.

Rosh (3:22): Rav Yehudah says that R. Shimon forbids a kerosene lamp, even of metal. It is not proper for any task, except for lighting, due to its smell. It is worse than a used earthenware lamp. Even though it is repulsive, one can put oil in it for anointing. The Halachah follows Rabah and Rav Yosef, since Rava tried to explain their reason.

Rif and Rosh (58a and 20:9): Rav permits moving a stick on which meat hangs, but not a stick on which fish hangs. Since it smells bad, he diverts his mind from it. Rav holds like R. Yehudah. The Halachah follows R. Shimon, who permits Muktzeh Machmas Mi'us.

Rambam (Hilchos Shabbos 25:11): If a Kli was Muktzeh Machmas Mi'us, e.g. an old kerosene lamp or Kelim for excrement, one may move them on Shabbos if he needs them.

Rambam (26:19): If leaves have a bad smell and they are repulsive, an animal does not eat them, therefore one may not move them. Therefore, one may not move a stick on which fish hang, but one may move a stick on which meat hangs.

Magid Mishneh: The Rif says that the stick on which meat hangs is a Kli, for it is normal (to reuse it). It is not normal [to re-use] a stick on which fish hang. After using it [once], he casts it amidst the [fire-]wood. Also the Rashba says so.

Beis Yosef (OC 310 DH Etz): It seems that the Magid Mishneh's text of the Rif was different than ours.

Ba'al ha'Ma'or (Shabbos 66b): A bloodletter's Kelim are Muktzeh Machmas Mi'us and Chisaron Kis. They are not useful for anything [else], even to cover a Kli. Since there is no use l'Tzorech Gufan, there is no Heter l'Tzorech Mekomam, except for Tiltul Min ha'Tzad (indirect movement).

Ran (66b DH Amar): Even R. Shimon, who permits Muktzeh Machmas Mi'us, forbids a bloodletter's Kelim. He permits only things like kerosene lamps, which can be used to cover a Kli. One would not use a bloodletter's Kli for this, since if it falls, it breaks.

Tosfos (Shabbos 19b DH Hani): Rav forbids moving mats [used to cover merchandise]. This is astounding, for on 128a we say that Rav holds like R. Yehudah [who forbids] regarding eating Muktzeh, and he holds like R. Shimon [who permits] regarding moving Muktzeh. Here Rav forbids moving! R. Tam answers that the mats are Muktzah Machmas Mi'us. They, or garments, are used to cover fish and other things that soil them. Rav permits moving what is Muktzeh because man removes it from his mind, and leaves it for business or a storehouse. On 156b, we derive from the mats that Rav holds like R. Yehudah. R. Tam explains that an animal that became a Nevelah on Shabbos is Muktzah Machmas Isur. It was not proper for even dogs to eat. Muktzah Machmas Isur is more stringent than Muktzah Machmas Mi'us. (Rav forbids eating on Shabbos an animal slaughtered on Shabbos - Chulin 14a.) The Gemara wanted to establish this like R. Yehudah, but rejected this. R. Yehudah forbids only Muktzah Machmas Mi'us, but perhaps not Muktzah Machmas Isur. This is a flimsy rejection. We conclude that Muktzah Machmas Isur is more stringent. The Gemara said that perhaps R. Meir permits only what was cooked on Shabbos, for one could have eaten it raw, but not what was slaughtered, for one could not have eaten it raw. This implies that R. Meir forbids Muktzah Machmas Isur. Regarding moving a used lamp, we say that R. Meir permits Muktzah Machmas Mi'us. He forbids only one that was burning on Shabbos!

Gra (310:7 DH v'Yesh): The Rosh says that Rav holds like R. Shimon regarding moving, i.e. regarding what a person diverts his mind from. See Tosfos 19b (that Rav holds like R. Yehudah regarding Muktzah Machmas Isur).

Rashba (Beitzah 28b DH Ravina): Ravina permits moving on Yom Tov a spit without meat, lest people get hurt on it. Why is this reason needed? A spit is Kli she'Melachto l'Heter on Yom Tov! Tosfos says that it is not a Kli. This is very difficult. Perhaps it is Muktzeh Machmas Mi'us. Even though Ravina and Shmuel rule like R. Shimon, who permits Muktzeh Machmas Mi'us, they hold like Rav Nachman, who says that the Stam Mishnah regarding Yom Tov is like R. Yehudah. This is the Rif's proof to rule like R. Yehudah regarding Yom Tov.

Question: Muktzeh Machmas Mi'us is forbidden even l'Tzorech Gufo u'Mkomo. This is clear from many places in Shabbos!

Answer (Teshuvas Rashba 1:606): Any Muktzah, whether Machmas Isur or Muktzah Mi'us, is permitted l'Tzorech Gufo u'Mkomo if it has the form of a Kli. The only exception is Kelim for which one fixes a place.

Poskim

Shulchan Aruch (OC 279:2): One may not move a Ner (that was burning during Shabbos) even l'Tzorech Gufo u'Mkomo. Some permit, but this is unreasonable.

Rema: Some say that if one is an Istnis and it is repulsive to him, he may remove it, since for him it is like a Geraf Shel Re'i. One who is stringent does not lose.

Taz (3): The Bach says that this should say 'one who is stringent will be stringent. One who is lenient does not lose.' If so, why did the Mechaber write in Sa'if 6 'Muktzeh Machmas Mi'us is permitted'? In any case it is permitted because it is like Geraf Shel Re'i! Rather, even though it is repulsive, it is not like Geraf Shel Re'i.

Shulchan Aruch (6): A Ner that was not burning on Shabbos, even if it is of earthenware and it is repulsive, even if it is of kerosene and smells foul, one may move it, for Muktzeh Machmas Mi'us is permitted.

Beis Yosef (DH v'Ifligu): Amora'im argue about whether R. Shimon permits only an oil lamp, or even a kerosene lamp, which smells bad. It seems that Rava and Rav Avya permit, like Rabah and Rav Yosef. The Rosh and Rambam rule like this. Also the Rif does, for he Stam rules like R. Shimon regarding Muktzeh Machmas Mi'us, and did not distinguish between oil and kerosene.

Magen Avraham (12): It is permitted only l'Tzorech Gufo u'Mkomo, like it says in 308:3.

Magen Avraham (13): This is only when it has the form of a Kli, like the Rashba says. See 518:3. (One may move a spit on Yom Tov to avoid harm to people.)

Mishnah Berurah (31): It is permitted because it has the form of a Kli, and it can be used to cover a Kli.

Kaf ha'Chayim (31): If it is so repulsive that it is not proper to use to cover a Kli, it is forbidden.

Kaf ha'Chayim (32): Nachalas Tzvi says that the custom is not to move a Ner that is Muktzeh Machmas Mi'us, lest people come to move one that is Muktzah Machmas Isur, for not everyone knows the laws.

Bi'ur Halachah (DH Ner): One may move it only l'Tzorech Gufo u'Mkomo. It is no better than any other Kli she'Melachto l'Isur. Eliyahu Rabah says that if one only designated it, but never used it yet, it is Kli she'Melachto l'Heter, for designation is not significant. One may move it even to avoid theft or loss. The Pri Megadim leans to say that the Rambam permits Muktzeh Machmas Mi'us only l'Tzorech Gufo u'Mkomo even if the Kli is not Melachto l'Isur, just it is repulsive. It seems that the Ba'al ha'Ma'or and Ran disagree.

Shulchan Aruch (OC 310:1): A stick on which they hang fish, even though it is repulsive, one may move it, since we permit Muktzeh Machmas Mi'us like R. Shimon.

Drishah (2): Also regarding Muktzeh Machmas Mi'us, R. Shimon permits even from the sun to the shade, for it is not considered Muktzeh. We distinguish only regarding things that are called Muktzeh, e.g. Kli she'Melachto l'Isur. Then it is permitted l'Tzorech Gufo u'Mkomo, and forbidden from the sun to the shade, even according to R. Shimon.

Mishbetzos Zahav (1): The Rambam permits 'only if he needs them', i.e. l'Tzorech Gufo u'Mkomo. The Drishah permits even from the sun to the shade. This requires investigation.

Mishnah Berurah (1): The stick is a Kli, since it is special for hanging fish. However, it is repulsive, for it is has a bad smell. It is Muktzeh Machmas Mi'us according to R. Yehudah, but we hold like R. Shimon, who permits.