From Mangled to Magnificent - The Step-by-Step Process
1. Remove the jaws - Flip the skull upside down and chisel away at the rock that's holding the jaws to the rest of the skull. Set jaws aside.

2. Clean out the skull - With the skull still upside down, scrape the rock away from the bone, layer by layer. Use brushes, picks and tiny hydraulic jackhammers and sandblasters.

3. Repair damaged areas - Using a fast drying clay, fill in cracks, sculpt missing parts and rebuild areas that are broken or distorted.

4. Build the steel armature - This step needs the skill of a specially trained blacksmith. Using heat and a hammer, he carefully shapes solid steel rods until they fit perfectly around the skull and jaws.

Reference: Information from The Field Museum website.