Summarize this article in one sentence.
It’s a good rule of thumb to do a deep clean on your grill twice a year. If your porcelain grill grates are really dirty, use a professional grill cleaner for a deep clean. Read the label on professional cleaners to ensure they are safe for use on porcelain grill grates. Most manufacturers will state if they are safe for use on porcelain grates. You can buy a professional grill cleaner online or at your local hardware store. Most grill cleaners come in a spray bottle for easy application. Let the grill cool down or apply the cleaner when it has been shut off overnight. Spray the cleaner all over the grates and let it sit. Then, use a clean grill brush to gently remove any dirt or food debris on the grates.  If the grates are really dirty, you may have to do a few passes with the grill brush. If there is a lot of deep grime caked onto the grates, you can also try spraying the grill cleaner and leaving it on overnight. Then, clean it off with the grill brush the following day. Wipe down the grill grates with a clean soft cloth or paper towels. This will ensure there is no excess cleaner on the grill grates so your food doesn’t end up tasting like cleaner when you grill it. Another option is to heat up the grill before you start grilling to burn off any excess cleaner.

Summary:
Get a cleaner that is safe for use on porcelain. Apply the cleaner. Remove excess cleaner before using the grill.