I put the painting of George under the tap in the bathtub and washed it off completely with a sponge. Yupo is a plastic "paper" and you can just wash the paint off so it was easy. If you want the paint to stay on the paper permanently without fear of rewetting it or smearing it, you have to spray it with an acrylic sealer at the end.
So...this is how it looks (left) when it's back to the paper. You can see the painting faintly but that's good because that helps me redraw it on the paper.
And then here it is (bottom) after I've redrawn it using watercolor pencils. I'm putting in some green fronds/leaves in the bg so it's not all one color or one texture and should be easier to work on when I start over. Since I'm going to do this all in one go, I'll start it tomorrow when I'm fresh and ready - at least, that's the plan.