I don't think I'd put foil on the grill if I were you. You'd do a lot of damage to the surface I'd think.
Actually to clean them, keep them very warm (more of HOT) and then take a THICK sponge and wipe it down while it is still heated. It comes off very nicely. If you don't do it immediatlely after cooking, then turn the grill on again and let it get warm. That plastic scraper thing is a waste.
Mishetta, are you using the suggested cooking times? I think a steak only takes about 5-7 minutes to do. Chicken just about that or a hair longer.