How to get something back from my mother-in-law?

I don't think we should be so abrupt. If your sister-in-law doesn't need it, don't. If she really needs it, you can solve it in the following ways.

Be sure to find a reasonable reason, for example, you need some jewelry to decorate the banquet or any important occasion, and then borrow it from the old man, saying that the jade bracelet will accompany the banquet and the old man will give it to you.

We must respect the elderly. The happier you are with her, the more right your older children will be, because the safest thing for the elderly is to have funds or finances, because they think their children may not be reliable. If you show filial piety and respect for the elderly. She has gained a sense of security in you and doesn't need her to keep her belongings. In this way, not only can you get this bracelet, but also other things of her own will be given to you.

Therefore, we must respect the elderly and learn to speak well. Actually, it's not that difficult between mother-in-law and daughter-in-law.

I wish you happiness, young and old.