How to prevent leftover paint from drying out in the can?

After finishing the work, there is usually some leftover (wood/wall) paint left in the can. However, due to contact with air, this paint begins to dry out and therefore only has a limited shelf life.

Is there a way to prevent/slow down this process?
I once heard that the very thin (!) coating of the remaining paint with (sunflower?) oil prevents air contact and thus aging?

Is that true?

Or is there another way?

Even if. Would you seriously open a 5-year-old paint bucket and start painting?

Even if. Would you seriously open a 5-year-old paint bucket and start painting?

Sure.. I have done it several times.. well... it wasn’t 5 years but definitely 3..4. For example, I painted the old wall of the neighbor’s garage with our leftover baseboard paint. The paint in the bucket had actually held up.. without any intervention. Small amounts of the other paints (for touch-ups) I transferred into screw jars (about 750 ml) and stored them in a dark, frost-free place... they have also been used. I also still have white paint (for wood) left and use it regularly for various small jobs (shelves, moldings..). Always close the lid tightly!!

Wrap 100% thick in cling film.

I learned from grandpa as a child,
to put the leftover paint cans upside down if there’s still some liquid left, you can always get to it. ;)
And it’s airtight too :oops:

I always place a layer of cling film directly on the leftover paint in the bucket. It has always worked well so far.