A reader has a method he says greatly increases the lifespan of a can of paint.
“Long ago I learned a technique to make paint last almost indefinitely–in quantities of 1 gallon of less (though it might be possible with current plastic 5-gallon buckets). Making very sure that the cans are tightly sealed, turn them over every year or two. Today I’m painting with a long since discontinued Flecto plasticized Varathane enamel. I first opened and used it 11 years ago, but had always flipped it every year or two. It does take about 3-4 days to dry, but I’m betting it was slow even back in the day. This is the third “opening,” and it’s behaved the same each time.”
When it is a plastic container the problem of air tightness is in the line of contact between the container and the lid. Look for a way of improving its air tightness. You can try this, put runs of cell tape to across the joint. Ensure the runs are flat close, overlap one another and are long enough to provide additional mechanical strength to withstand turning stress during flipping, then put a note on it “Please Do NOT Disturb”.
Good ideas. Thanks