Fill a bucket with one or two gallons of hot water. Add a couple of jets of good dishwashing liquid and stir until well blended. To season your flat surface grill for the first time, pour about two or three tablespoons of oil directly onto the entire surface of the Blackstone grill. This is an important habit so that, when it comes time to clean the grill with a flat top after a large meal, it's a simple process that doesn't involve burning sticky sauces or layers of food residue.
If it oxidizes slightly, a Blackstone scourer or grilling stone will suffice, but for more intense and deeper levels of oxidation, experts, such as Lodge Cast Iron, recommend white vinegar. This means that too much exposure to water and air is enough to turn the flat surface from black and shiny to rusty and opaque.