white elephants

White elephants are possessions that cost more to maintain than they're worth—burdensome to keep, difficult to dispose of.

The term comes from a story about Southeast Asian kings gifting rare albino elephants to disfavored courtiers, knowing the sacred animals couldn't be put to work but required expensive upkeep.

A white elephant sale is a fundraiser where people donate unwanted items: We cleared out the garage for the church white elephant sale.