Preheat oven to 325 degrees. Spread boiled peanuts on Silplat lined baking sheet and roast for 30 minutes, stirring once or twice. Reduce heat to 250 degrees and continue roasting for 1 1/2 - 2 hours, stirring the peanuts once or twice, checking for brownness. Turn off oven, open the oven door for 5 minutes to lower the temperature, and leave the peanuts in the oven another hour or two, or overnight to crisp up.