The crude container that I made with a lead sheet contains 16 oz. of cold-pressed walnut oil. I’ll leave the oil in the container for several months before straining it into a jar, like the one in the upper-left of the photo.
The lead imparts drying qualities to the oil making it excellent for mediums. The oil remains flowing but is firmer than usual and holds a stroke. Mixed 1:1 with turpentine it creates a medium that is almost as good as my usual medium. In fact, I’ve been substituting the linseed oil in the jar in the photo for the black oil I normally use in my medium.
If you want to make drying oil, keep the container covered and occasionally shake it to ensure it doesn’t form a skin.
When it’s ready, filter it through cheesecloth when you decant it.