I have a Weber Genesis with cast iron grates. My wife, concerned about the risk of stray metal bristles getting into our food, bought me the Grill Rescue stem cleaning brush. Now I don't mind the brush (the reviews actually seem to be strong), but I'm concerned that the steam cleaning be too aggressive and will remove the season from the cast iron grates. I can't find anything about this topic elsewhere online, so I figured I'd ask the opinion of the experts here. What do you guys and girls think?