What to do with that not-so-great painting
Additional Information
Sometimes a painting dies a sad and painful death, but I'm too frugal to throw it away. I try to learn from the process.
Recently I've found new value to these defunct paintings. I use them to experiment on. Since they will never see the inside of a frame, I can try things that on a more successful painting, I would be much more hesitant to try.
Maybe these are studies for my next painting? I love that thought I review the "failures", see what worked and what didn't and then decide which way the piece will go.... should I gesso over it salvage the canvas, or think of it as an experimental piece where I will try to work out what wasn't successful?
I may never resolve the issues on the painting but it gives me a playground to try new and perhaps daring things that I may not wish to try on a more successful piece.
It is just paint, after all! 
