How To Season A New Cast-Iron Pan
The surfaces of a new cast-iron pan are porous and have microscopic jagged peaks. You season a pan by rubbing it with oil, heating it for 30 to 60 minutes in a 300-degree oven, and then letting it cool to room temperature.

The oil fills the cavities and becomes entrenched in them, as well as rounding off the peaks. By seasoning a new pan, the cooking surface develops a nonstick quality because the formerly jagged and pitted surface becomes smooth. also, because the pores are permeated with oil, water cannot seep in and create rust that would give food an off-flavor.

Unless you use your cast-iron pans daily, they should be washed briefly with a little soapy water and then rinsed and thoroughly dried in order to rid them of excess surface oil. If you do not do this, the surplus oil will become rancid within a couple of days.
How To Season A New Cast-Iron Pan