the idea: use the collected paint at the bottom of the dirty paint jar
I started doing this in college when I noticed the ever-remarkable occurrence of settling paint. See, normally I use to glass jars for my paint thinner. One is more-or-less clean and that’s where I rinse my brushes while the other is the collection of the dirty paint thinner (think water that’s turned brown because you’ve washed your paintbrushes too many times).
If left alone for a long enough time, the paint settles to the bottom of the dirty jar accomplishing two things.
1.) The now clean paint thinner (which rests above the gray paint sludge) can be poured out and reused, eliminating the need for simply disposing of the chemicals in the paint thinner. Also, money saver.
2.) The gray sludge is always a different color and is great to use for shading and creating depths in artwork.
In today’s picture, the outer gray part of the pink-ish circles were made with paint sludge. This painting is at a very early age (obviously, you can actually still see the canvas!), which is one of my favorite times to use the paint sludge.
Extra bonus: this idea constantly makes me feel like a mad scientist.