The stuff of oil painting can be harmful and you’d be well advised to learn about the nature of the related materials. Many pigments are made from hazardous materials including heavy metals. If you use mediums or solvents, you can expose yourself to airborne toxins such as turpentine or mineral spirits. Aside from the problem of exposing yourself to these substances, there is the problem of detritus. Oil painting related garbage is considered hazardous waste which is not supposed to go in the regular garbage or down the drain. So what to do with it? You can start collecting it and eventually make a trip to the toxic materials dump.
Some painters save their palette shavings or other left over dried up paint. Check out Matt Bahen’s “Mountain” - an accumulation of years of wiping extra paint off his brush!
I collect my solvent and let is settle in a number of containers starting with my Min Shin. This is an airtight portable metal jar for plein air painting. I bought this many years ago when I would go painting in the landscape. After it separates in there, I skim the clear liquid in another bottle and reuse it. Then I periodically dump the sludge that accumulates in the Min Shin in a paint bucket where I let it dry. And this has also accumulated over the years. You can precipitate and reuse both your solvent and your oil in this way. Here is my reuse system:
