If your cast iron is new, it probably has come to you pre-seasoned, meaning it already has a coating of oil on it. You can put another coating of any kind of vegetable oil on it inside and out and bake it in a 350o F oven. Put it upside down in the oven with something underneath to catch the excess oil. Let it bake for an hour and then turn off the oven, leaving the cast iron in it, and allow the pan to cool down. Use a lint-free cloth to wipe down the pan and it’s ready to use! Use the same method for older, rusted cast iron and it will be as good as new.
When you cook with cast iron, you don’t want to shock it with extreme temperatures like pouring in ice water after you’ve heated it. After cooking, if there are bits of charred food in the pan, scrape off as much of the bits as possible with a wooden spatula and run hot water in the pan. Some people want to use soap but that isn’t good for the nice seasoning you’ve worked so hard to put on the pan. Hot water and some gentle scrubbing with a sponge or dishcloth should get everything. If there is still a spot or two, put some coarse salt on the spot and use a sponge or dishcloth to rub the spot away.
While I don’t do this every time with my cast iron, it is recommended to dry the cast iron off and heat it gently on the stove, then put some oil in it and rub it around with a lint-free cloth. Wipe all excess oil off and turn off the stove to let the pan or pot cool. Your pan is now ready to use for the next meal.
If you have a lid, be sure to season that, too. And it’s best to use wood or silicone utensils except for the occasional metal utensil as long as you’re not scraping the pan with it.
For further tips you can go to these sites: