You can create a perfect non-sticky surface on cast iron pans like this:

- clean well with strong soap and a metal sponge until it's one smooth silver surface

- put a few drops of flax oil on a paper and rub the pan with it (also inner sides)

- take off all excessive oil with a dry kitchen paper

- remove any non-metal handles from the pan

- open your windows

- heat your oven to the max and put the pan in for about 20 minutes

- repeat about 5 times

After using the pan, wipe with a kitchen paper. Maybe a little bit of warm water, better not. Never any soap.