I use one all the time. There is no secret to it. Every time I use it, I wash it with dish washing detergent just like everything else.
I don’t scrub the outside, just rinse it. I then put it on the burner for a short time and spray the inside with Pam. That leaves too heavy a coat so I take a paper towel and wipe it as dry as the towel allows.
I have never had even the slightest hint of rust.
My Mother cooked on one for nearly 70 years. I think it was the same pan too. She once wondered out loud, how many thousands of meals it had cooked.
[Pam! Pam! Pam!]
Do I smell? Pantene! Do I smell Pantene?
I do something similar, but I bought a Misto sprayer and filled it with olive oil.
-PJ