After choosing the comal that's right for your needs, it's important to “season” it before taking it for a spin. First you want to wash your new comal thoroughly with warm, soapy water and immediately dry it completely after rinsing. Comals are highly susceptible to rust, which is the reason for seasoning it in the first place, so it's always important to dry it well after washing.
Once your comal is clean, the seasoning can begin. Using vegetable oil, lightly coat the entire surface of the pan. This protects it from water, and ultimately, rusting. Once it's been oiled, bake it in an oven at 350 degrees for an hour. Remove it from the heat and allow it to cool. Wipe it down with dry towel and then reapply the oil and bake it for another hour. This time, leave it in the oven to cool overnight. In the morning, wipe it down with a clean, dry towel once more and it's ready to rock.