Although most manufacturers don't tell you to season carbon steel pans before their use, their pitted surface requires seasoning to create a non-stick area. You can season them just as you would cast iron pans--baking a coating of oil into the surface in a hot oven. Use this method only with oven-safe carbon steel pans. Properly seasoned steel pans won't have to be seasoned again unless the first coating gets scraped off.
Heat your oven to 400 degrees and place the carbon steel pan in the oven for 10 minutes to heat the surface.
Remove the hot pan from the oven using oven mitts. Saturate a paper towel with vegetable oil. Hold the towel with tongs and rub it over the interior and exterior of the carbon steel pan while holding the pan with oven mitts.
Place the oiled pan back into the oven, upside on a rack above a baking sheet, which will catch any dripping oil.
Bake the pan at 400 degrees for one hour.
Let the pan cool completely before removing from the oven, reoiling and baking a second time so the surface turns black, indicating a proper seasoning.
Do not use soap to clean the seasoned pan. Scrub the interior with hot water instead.