A friend of mine gave me some stuff he picked up from Sams Club, it’s a stainless steel grill cleaner that works really well. Cuts grease and build up great. I use it on the grates, like one above, in a garbage bag and let it sit in the hot sun in the summer for a few hours. Then clean them with soap and water a few times. If you have Sams Club access, let me know and I’ll get a pic to you.
For the smoker, I just The the grates on my grill and turn the heat up to high and that does the trick with the brush.