26 CFR 25.2518-2 - Requirements for a qualified disclaimer.
(1) Requirements. A disclaimer is a qualified disclaimer only if it is in writing. The writing must identify the interest in property disclaimed and be signed
Chapter 802g - Disclaimer of Property
(c) The disclaimer shall (1) describe the interest disclaimed, (2) be executed by the disclaimant in the manner provided for the execution of deeds of real