A kli is susceptible to tumah. If it’s primary function if removed, is it still susceptible to tumah? It is has a secondary function that resembles the original function, it retains the tumah. If it has a secondary function that is unlike the original one, then it’s a Machlokes if it could still have tumah or not. So, for example, a bell with a clapper inside is a kli bc it functions as a noisemaker. If the clapper is removed, does it still have tumah? Some say it still has tumah only bc it could still make noise by hitting it on the side of a pot, while others say the fact that it can be used as a cup is enough to retain the tumah.

Utensils that function only for animals do not accept tumah. Nontheless, a metal shoe for animals does accept tumah bc of a secondary function it has. Some say it has to resemble its main function, so the secondary function has to be something like a person using the shoe in times of war to flee. Others hold the secondary function does not have to resemble the original one, and even functions that drinking from the shoe or using it for oil cools give it susceptibility to tumah.

All agree regarding the unique tumah of midras (if a zav/Zavva sit on a chair made to sit it becomes an av hatumah) that if the chair/mat no longer has a primary function of sitting then the tumas midras is lost.

Regarding the jewelry of ירושלים של זהב- r Meir holds it a a burden and not jewelry at all and one is biblically prohibited form wearing it on Shabbos. The Rabanan say it’s not a burden but it can’t be worn bc someone may take it off and come to carry it. R Eliezer says it may even be worn ideally, bc since it is only worn by very distinguished women, there’s no concern they’d take it off to show someone else.

Tiaras are a dispute in the genara if they can be worn. Some say they are reserved for distinguished women who wouldn’t take them off.

The Gemara notes that there’s no question about wearing two belts on Shabbos. Rashi explains it is certainly forbidden bc the second belt is a burden.

A ring without a signet is forbidden rabbincally bc a women way show it off. The mishna implies one with a signer is a total burden and biblically forbidden. It seems the signet is the essential part of the ring.