We’ve discussed the rule of bosis for muktzeh also becoming muktzeh. The gemara introduces the concept of a בסיס לדבר המותר ולדבר האסור- where the bosis Is both for a muktzeh and non muktzeh item. If there is a basket that holds both a rock and fruits, where clearly the fruit is more significant than the rock, the basket is not muktzeh.

Even if the muttar item is only slightly more significant than the muktzeh, the base is not a bosis, like the case of a shovel holding both ash (prepared for usage) and woodchips. (Muktzeh)

Significance is relative, so broken wicks (muktzeh) in the Galil where there was a shortage of flax for wicks, would be more significant than oil. But outside the Galil, oil would be more significant than broken wicks.

There’s a special leniency to move muktzeh that is repulsive and disturbing, like a pale of excrement

The “coppersmiths bed”- a portable bed that is made to take apart and reassemble. As long as the pieces are not assembled “tightly” and one does not nail anything in, there is an opinion that it is permitted to assemble the bed on Shabbos and it is not מכה בפטיש bc the loose nature of the building is not “final.” (There is a dissenting view that forbids it.)

Sparks do not make a kli into a bosis bc they are considered to have no substance.

Generally, there is a dispute if one is allowed to indirectly extinguish a fire in Shabbos to prevent loss of money. Everyone agrees that it is forbidden to place a cup of water under falling sparks bc it may lead to direct extinguishing. Moreover, to protect that scnenario, the Rabbis dont allow setting up the cup of water even on Friday.

Hatmana- insulating food- is forbidden on Friday if the material adds heat. (Bc it may lead to insulating with ash/coal mix, where one will be tempted to stoke the coals). Examples of forbidden materials is olive pulp, manure, salt, lime, sand (even dried out.) wet straw, grasses, shreds of clothing.

With intense heat, like pulp of olives, it is forbidden even if the material is surrounding a box that wraps the food. But with less intense heat, like sesame pulp, it is only forbidden if the material directly wraps the food.