Is it permissible for my daughter to continue wearing a vest made of pigskin, or is that forbidden?

Scholars differed regarding the purity of hides from dead animals, including pigskin. The preponderant opinion is that all of them become pure through tanning, due to the generality of the Prophet’s (peace and blessings be upon him) saying: "When the hide is tanned, it becomes pure." Therefore, there is no objection to utilizing pigskin after it has been tanned and prepared.