Hello Bill: Great topic!
When you first suggested to me that I do that on my elf girl painting, I thought - "Sand it! He's crazy!"
But I did it anyway and it really worked well to smooth it out and get rid of unwanted paint ridges.
It also accomplished another thing - it gets you away from saying to yourself "that part is perfect" and
loving any one part of the work too much. Because of the sanding, there were parts of that painting that I painted into and over two and three times - each time they got better.
