Methods of storing a precursor which decreases the precursor decomposition rate. A vessel is provided, where the vessel has an outer surface made of a first material, and an inner surface made of a second material. The first and second materials are different. A tantalum containing precursor is placed inside the vessel, and the vessel is heated to a temperature between 600°C and 15O0°C. At least part of the precursor is withdrawn from the vessel.