Put your oven on preheat of 350 degree Fahrenheit.
Scrub your cast iron cookware with steel wool to take off the protective layer over it. If it is old cookware, the steel wool will also take off any rust that has accumulated during the cooking. After scrubbing, wash the cookware with soapy water and a cloth. Dry the cookware completely using the towel.
Now use a paper towel to scrub oil over the whole surface of the cookware. You should coat every part of the cookware, including the handles; no area should be left dry. You can use vegetable oil or melted shortening for the purpose. All interior and exterior parts of the cookware should be covered.
Place the cookware in the oven and position it right in the centre. Do not cover it with anything.
Leave the lid outside an bake it in the oven for an hour. If you have more than one cookware to season, place them in the oven together depending on the capacity.
Check the cookware after an hour. Let it cool down in the oven before you remove it with paper towels, protecting your hands well.
If you are not satisfied with the first round of seasoning, you can do it again for better results.