This is the final picture of another new medium.
First (my upload wouldn't capture in sequence, so, bottom first):
ordinary pastels were used, then I over-painted in milk (I thought 'Long-life' may be appropriate seeing that its organic and visualised this picture eventually turning green or being eaten by my cat)
Apparently Edgar Degas was known for this technique. Jolly good for him. Me? not too sure.
I'm busy with another pastel now. lets see how this one turns out. Think I'm going to try snake urine.