Remove the label from the can. Try to remove as much of the adhesive as possible.
Place the can on its side in a large pot. Fill the pot with water, making sure the can is covered by at least 2 inches.
Place the pot over high heat and bring to a boil. Reduce heat to medium or medium low, making sure the water is at a simmer. Cook for 2 ½ hours, adding more boiling water as needed.
Remove the can from the water carefully. Place on a rack and allow it to come to room temperature before opening.
Recipe Notes
It is important that the water level remains above the can. Check periodically, and add additional boiling water as needed. Also, it can be dangerous to try to open the can before it cools; wait until it has come to room temperature before opening.