Your cast iron isn't ruined, but it might need reseasoning.

Probably not permanently ruined, but it might need some love.

Modern dish soap isn’t harsh enough to destroy a well-built seasoning overnight. The real issue is the soak itself — prolonged exposure to water can make seasoning lift and flake, especially if it was thin or uneven to begin with. Soap helps break down oils, so a full night could strip weaker spots.

The fix: wash it normally, dry immediately, and see what you’re working with. If the surface looks patchy or feels tacky, just scrub off any loose bits, dry it on the stove, then apply a thin layer of oil and bake it at 375-400°F for an hour. That’ll bring it back.

Cast iron has survived worse than a night in the sink.