This required a box knife and patience.
I had both. And what was funny about the whole thing is my mom coming in to watch me.
She watched me mix the plaster and fill the shoes. Then I jokingly told her to come back in two hours and watch me tear the shoes apart.
And she did.
Did I mention that she used to work in a shoe factory? I asked her what she did and she said that she sewed the tongues and heels in mens shoes.
I think her knowledge will come in handy when I get to that point.
Here is a picture of the filled shoes, prior to my tearing them apart to get the last out. I forgot to take a picture of the 'tearing apart' part.