Get a Cover!: The first thing you need to do to keep your stainless steel grill looking new is to take care of it. This means you need a good quality grill cover. The cover comes off right before you flame on the grill and it goes back on as soon as it is cools. This will keep the elements off your grill and keep it looking good. A good grill cover lets moisture out but not in. A cover that lets moisture in is pretty much worthless and a cover that traps moisture inside is pretty much worse than a no cover at all. Look for covers that let moisture out. They are typically made from vinyl and not just any vinyl but thick, heavy vinyl. You can also get covers made from SunBrella or Denier, these are also great materials. The cover should have a felt liner on the inside to absorb excess moisture and draw it away from the grill. The felt liner also protects the grill from the cover itself by padding the cover.
Clean your Grill: Now that you've got a cover, you will need to keep you grill clean. Grease and food particles will corrode even the highest quality stainless steel given enough time. This is particularly a problem as we tend to use more acidic marinades and sauces on the grill. These will kill your grill no matter how much money you spent on it. Now, nothing I say can get you to clean you grill on a regular basis, but think about how much you spent on that grill of yours. Now, divide that number by five. If your grill lasts five years (slightly more than average) this is the amount of money you spent on your grill per year. If you can increase the lifespan of your grill by only one year, you just cut the cost per year by 20 percent. Get the most out of your investment by cleaning your grill.
Cleaning Stainless Steel: When it comes to cleaning stainless steel you will need to remember that this material will scratch easily and when it does you’re either facing a power buffer or just living with it. So, never use steel wool or metal brushes to clean your grill. You also need to avoid using abrasive cleaning agents. Try kitchen appliance cleaners or stainless steel cleaners that you can buy in most stores. You can try appliance stores because they tend to know a little more about what they are selling. One cleaner I've tried is Bayes BBQ Grill Cleaner. This stuff works as a cleaner and a protectant so it not only cleans your stainless steel, but helps keep it that way. Other than that, you should clean your grill with a soft cloth and a good quality non-abrasive cleaner. This really is about all you’ll need. There are stainless steel polishes, but remember than anything that leaves behind a film or finish will be subjected to the heat of your grill. Stainless steel polishes can discolor under intense heat and make your grill look worse, not better.