I just learned, that Winsor&Newton has a recycling program for old paints and markers. Which is what we need all over the world. Oftentimes pigments and paints need to be safely disposed of as toxic waste, so for artists, who use a lot, disposing of old paint can become an issue. (If you're responsible...)
So maybe it's worth looking into it and spread the word: https://www.winsornewton.com/en-ca/pages/recycle-art-supplies