Thanks, Deb and Marla.  I've chosen to use a piece of Saran wrap just under the cap of the gesso jar.  The cap already has an inner seal, and the wrap might also help seal the threads.  I've not had any trouble with the gesso degrading, it's just the dried bits cracking off the cap and getting into the gesso that I was concerned about.  Thanks for writing!


On Sun, Feb 3, 2019 at 7:48 AM Marla Coppolino <[log in to unmask]> wrote:
Try putting a blob of Vaseline petroleum jelly around the thread of the container and lid before closing. That makes a more airtight seal, plus it makes it easier to open and close the jar.


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