When your silicone has cured overnight it's time to de-mold those parts. The easiest way is to get an air gun and put the nozzle in the seam between the 3D printed part and the silicone. When you blast it with air it tends to pop the parts right out. Barring that, you can work your way around the rubber, pulling the sides away from the mold, shimming the seam with popsicle sticks, and pulling gradually until the rubber gives way.