TotalBoat Gleam varnish has a shelf life of at least 1-2 years when unopened, provided it is stored correctly. Similar to most other 1-part varnishes, the shelf life of an opened can of Gleam spar varnish depends on how well the container was sealed and the remaining varnish quantity, ranging from a few weeks to a year. Proper storage conditions, including temperature and humidity, are crucial for maximizing shelf life, as indicated on the label.

To extend the shelf life, ensure the can is tightly sealed. Inadequate closure can lead to solvent evaporation, causing the varnish to dry out. Storing Gleam with less than half a can left can also impact its consistency. If the varnish thickens, straining it before use is necessary, although this will shorten its shelf life.

Some methods to prolong varnish shelf life include transferring leftover varnish to a smaller container to minimize air exposure or using products like Bloxygen to displace oxygen from the can. Bloxygen, containing inert argon, prevents the varnish from skinning over by removing oxygen, preserving its quality.