From what you describe, it sounds as though you have a GOSM which many of us use (myself included, I have two). If yours has a drip pan around the heating element, remove it and scrape out any congealed grease and other drippings with a plastic putty knife and discard. Same for the side walls. No sprays or degreasers as anything left is "seasoning." Before you cook anything, fire it up for a dry run and get her good and hot with just a few chunks of wood and/or charcoal for an hour or so and that'll sterilize the cabinet just fine. The racks can be cleaned with any commercial grill cleaner and a wire brush, just be sure to rise really well with a garden hose. Or just run 'em through the diswasher once or twice, if ya got one.
Good luck and keep smokin'!