How do you get a warped o-ring to flatten out?

To flatten a warped O-ring, you can soak it in warm water for a few minutes, which helps soften the material. Afterward, gently stretch the O-ring while it’s still warm, or place it between two flat surfaces and apply light pressure. Allow it to cool in that position to help retain its shape. If the O-ring is significantly damaged, however, it may be best to replace it.