: Hi Jay,
: An old 'trick' with tins of varnish or paint is to put clean
: marbles into the tin as you empty it, that keeps the air space
: at a minimum and the paint/varnish fresher.

Another way to lose your marbles while boat building !

I'm not a big proponent of using old varnish for a new project. Two or three years from now, when I put a fresh coat of varnish on the boat, I'm going to buy a FRESH can of varnish, and probably not use it all up. Saving small quantities of varnish to use on other projects (paddles) or for touch up over scratches or over larger repairs, makes a lot of sense. But I find it more convenient ot pour the varnish into a smaller bottle. It takes less space on my shelf, and I can look through a glass bottle to see if the stuff has congealed. Now if the bottle is still a bit too large then filling the excess space with an inert gas (propane, nitrogen, CO2, etc.) to displace oxygen, or using solid items like marbles or ball bearings, would make sense. If you have any thinner for the stuff it might be good to add a few drops to replace what evaporated from the open can while you used it, too.

But after a year the stuff is probably going to be junk anyhow--so mark the date you used it on the label, and test any old varnish before using it on a good project. It is a mess to clean off if it doesn't set up right.

PGJ