Here "in their hand" stands for what they own. AT: "that were in their possession" or "that they had" (See: [[rc://en/ta/man/translate/figs-metonymy]])
"their earrings." Possible meanings are 1) the gold in the earrings could have been used to make more idols or 2) they took these earrings from the city of [Shechem](rc://en/tw/dict/bible/names/shechem) after they attacked it and killed all the people. The earrings would have reminded them of their sin.