Depends on your definition of clean. Personally, I lay a sheet of foil down -or- a drip pan as often as possible. Probably about 60% of my cooks. I never foil when I grill (using the Flame Zone setup) though. I have come to the point that I don’t really stress over the inside. I keep it tidy, but more often than not, there’s evidence that it’s cooked in. What’s funny is that I am much more picky about keeping the exterior squeaky clean. I love a nice shiny SS MAK sitting on my back patio
**edit: I didn’t mention that I have two stiff metal scrapers (paint section at Home Depot). One wide and one narrow. They work wonders when it comes time to scrape the crusties away. Prior to scraping, I always make sure that the MAK has run at 375°+ for a bit to harden the gunk up. Makes for easy scraping.