I have always pulled the grates and steam cleaned them when possible, or take wet rags and wipe the grates until they show clean ( I dont like to see the black marks on my food, sear marks are fine, but not dirt marks)
On my new reverse flow build, I installed a full length drip pan, plan is to be able to use one of those quart size pump up garden sprayers and wash the grates down after the smoker heats up, hit them with grill brush , then spray them off again. Also the full length pan will catch All drippings and grease, and it will all be flushed out the drain.