I've got a well seasoned, never soap washed iron frying pan that I love and take care. This pan used to work well and not stick at all. Untill now.
There are now small white stains that make potatoes sticking to. Just potatoes (the last I bought, "agatha" variety), not other food.
To correct that I tried to heat up salt (2mn) and re-seasoning (1mm of olive oil, until smoke appears, I put it under cold water and wipe with paper towels)
It didn't work, white stains are still there and potatoes still stick to.
What may I do? Do I need to wash it with soap? I don't want to do that in order to not break the seasoning, but if I can't do anything else...