MB3 92a: Jewelry on Shabbos (303:17-19)

If something can't be worn in reshut harabim on Shabbos, can it be worn in a place where carrying is permitted (e.g. a courtyard with an eruv)?

Wearing a ring on Shabbos or wearing pins in one's hair on Shabbos.

Using a needle as a pin for a hairnet vis-a-vis muktzah.