The best way to season a cast iron pot or pan is to fry fish, cracklins, bacon etc. in it several times and clean with salt.
The best way to clean a seasoned cast iron pan or pot is to scrub it clean with salt and very little water, then rinse. Salt removes anything that might have stuck and will kill just about anything Ask the Carthaginians). Cleaning with salt leaves a
light coat of oil in the pan to prevent corosion.
The biggest problem with cast iron today is that it is only cast. My old pots and pans, including my griddle Norm, Have milled cooking surfaces. If you are buying new and can't find milled surfaces, look for ceramic coated cast iron, which will compete with most non-stick surfaces and don't require any seasoning at all.