How to remove stains from non stick PTFE cookware?

Many of the cookware are coated with Polytetraflouethylene (PTFE). We know these non-stick surfaces as: Teflon, Teflon II, SilverStone, T-Fal,  Supra, Resistal, etc.

The cooking surface over time gets either discolored or stained. These stains can be removed by filling the cookware with one of the following solutions, and let it simmer on low to medium heat for 15 to 20 minutes.
Solution #1
Oxygen bleach: 3 Tablespoons
Dish Detergent: 1 Tablespoon
Water: 1 Cup
Solution #2
Automatic dishwater detergent: 3 Tablespoon
Water: 1 Cup

To remove stubborn stains,  use nylon sponge pads and dish soap. Don't use metal sponges.