As a construction accountant, an important piece of paper when processing accounts payable checks are lien releases. Every check you intend on handing out must have a lien release reciprocated. When you pay a contractor, lien releases stipulate that they have been paid in full for work performed through a certain date. The lien release must include the amount paid, the subject property address and the date that work has been performed through. Make sure the language "waives and releases its lien and right to claim a lien for labor, services and materials" is mentioned. If a NTO or notice to owner has been furnished, this mean the contractor has a subcontractor working and this sub wants you to know he wants payment. If you receive an NTO make sure the contractor provides you with a release from their sub that they've been paid. Otherwise you will be responsible for paying the sub and they could potentially lien the property for payment.