N.H. Rev. Stat. Ann. § 451-A:2

If such lien remains undischarged for a period of 60 days after work has been completed, the lienholder may sell such article at private or public sale, and the proceeds, after first paying the expense of the sale, shall be applied in payment of the debt, the balance, if any, to be paid over to the county treasurer of the county where the sale is held, in trust for the debtor.