Abstract: A method or process for substituting an inert gas or blend of inert gases for ambient air in the head space of a container filled with leftover oil-based finish prior to sealing the lid. Even a tightly sealed container of leftover paint, stain, varnish, or other oil-based finish, will thicken, gel, or skin over with time. This occurs because the oxygen that is sealed in the storage container continues to react with oil-based finishes. The process involves using an aerosol can filled with the inert gas or blend of gases to displace the oxygen from a container that has leftover oil-based finish in it. After the oxygen is flushed out of a container with the gas, the lid is sealed tightly. The inert gas or blend must be heavier than oxygen and sink down to block oxygen from the liquid surface. Because gas or blend is heavier than oxygen, it will separate the liquid surface from any oxygen that may remain in a container.