How to Clean Cast Iron
To clean cast iron cookware, use a plastic scrubber and hot water to remove food. Then, dry the cast iron item carefully with a dishcloth and store it in a dry place. To be extra sure the cast iron is dry, place it on a hot burner and let it warm up, so any water will evaporate. If you're storing the item for more than a day or two, cover it in a light coat of cooking oil first. To get rid of baked on residue, mix up some oil and a few spoons of salt in a small dish, then use a paper towel or cloth to scrub the iron pot or cooking dish.
Make sure your cast iron is seasoned. Seasoning cast iron creates a seal over the metal, preventing rust and creating a nonstick surface. Some cast iron cookware comes pre-seasoned; read the packaging or ask a store clerk if you aren't sure about yours. If you've had your cast iron cookware for awhile and don't know if it came seasoned, it's best to take the steps to season it, just in case. Read How to Season Cast Iron Cookware to learn the best technique for seasoning your cookware. Wash cast iron with hot water. Use a plastic scrubber to remove food. Be careful not to scrub too hard, so you don't remove the seasoning. Since the surface is nonstick, a light scrubbing should do. Do not use soap on cast iron. It's abrasive to the iron's surface, and may remove the seasoning. Dry the cast iron thoroughly. Use a dry dishcloth, and make sure you don't miss any spots, especially on the inside of the cookware. To be extra sure the cast iron is dry, place it on a hot burner and let it warm up for a few minutes, so any extra water will evaporate. Coat the cast iron lightly in cooking oil. Dab a paper towel in olive, grapeseed or canola oil and rub it over the cast iron. This seals the metal and makes sure no moisture causes the cast iron to rust. If you use your cast iron cookware daily, this step is not necessary. Only coat the cast iron in oil if you're storing it for more than a few days. Store the cast iron in a dry place. Take care not to stack a wet pot or pan on top of the cast iron. Scrub with oil and salt. Mix olive oil and a few tablespoons of salt in a small dish. Pour the mixture into the cast iron cookware. Use a paper towel or other cloth to scrub the salt into the cast iron, focusing on the areas with caked-on food. Continue until the food remnants have all been loosened, and dump them in the trash. Wipe the cast iron with an oiled cloth. Take a second paper towel or cloth, dip it in oil, and wipe the cast iron until it is clean. If the food is impossible to dislodge, bake the cast iron. Set the cast iron cookware in the oven. Turn the oven to the self-cleaning setting, and let it run its course. Before trying this method, be aware that this method will require re-seasoning the cast iron. The cookware will emerge covered with ash and a layer of rust. Don't use it until you've followed the instructions for cleaning rusty cast iron cookware. Make a solution of white vinegar and water. Find a container large enough to hold your cookware. Fill it 3/4 of the way with a solution of half vinegar, half water. Submerge the cookware in the solution. Allow it to sit for three to four hours, checking it's progress along the way. The vinegar should dissolve the rust. If the rust isn't fully dissolved after four hours, remove the cookware from the solution and use a nonmetal brush to brush off the remaining rust. Don't leave the cookware in the solution for more than four hours, as it will start causing the metal to degrade. Rinse the cookware and dry it thoroughly. To make sure it's completely dry, heat it through on the stove, or bake it in the oven for a few minutes. Coat the cast iron lightly in cooking oil. Dab a paper towel in olive, grapeseed or canola oil and rub it over the cast iron before storing. Season the cast iron again before cooking. Since you burned off the protective layer of seasoning, you'll have to re-season the cast iron before using it again. Otherwise, it won't provide a nonstick cooking surface, and it may begin to rust. Coat the cookware in olive oil and bake in a 350-degree oven for one hour. You'll have to cook with the cast iron several times before it's fully seasoned, but this method will start the process. Stores that sell cast iron usually carry seasoning products to apply to your cookware. Try one of these if you'd prefer not to season your cast iron yourself. 
Make sure your cast iron is seasoned. Wash cast iron with hot water. Dry the cast iron thoroughly. Coat the cast iron lightly in cooking oil. Store the cast iron in a dry place. Scrub with oil and salt. Wipe the cast iron with an oiled cloth. If the food is impossible to dislodge, bake the cast iron. Make a solution of white vinegar and water. Submerge the cookware in the solution. Rinse the cookware and dry it thoroughly. Coat the cast iron lightly in cooking oil. Season the cast iron again before cooking. 