If you cook with cast iron here is a few tips to protect your investment:
Soap will attack and erode the seasoning of your pan if you soak in soapy water for more than a little while.
The metal can buckle if you expose a hot-off-the-stove pan to cold water.
Washing your pan in the dishwasher will also erode the seasoning, dishwasher detergent is too harsh.
You never want to use a metal scratch pad to clean your cast iron, unless you're removing layers of rust. For everyday cleaning just use a nylon scrubber.
Even a pan that is coated with rust or a layer of char can be rehabilitated, you'll need to scrub with a steel wool pad, wash well in warm soapy water and scrub while pan is wet. Repeat as many times as necessary to remove all the rust then re-season.