Riddle me this, regarding your unused grill grates

[BillA from CA]

I basically just let my grill preheat for a few minutes over the coals until I am satisfied that any (most?) combustibles have burned off, and then I scrub the bejesus out of it with one of those densely woven metal scrubbing pads before throwing the food on it. I seldom scrub the grill after I cook on it because it tends to contaminate the scrubbing pads pretty badly with mop sauce or whatever goop was on the food.  On rare occasions I will leave the vents open after I take the food off and let residual stuff burn off before I shut down after a cooking session. I never intentionally coat the grill with anything prior to storage, but in SoCal we don't have many mold issues, especially with the frequency that I use the grills. If I had concerns about mold I would probably spray it with a bleach solution before storage but I have no empirical evidence that shows that would even work.

[Dsorgnzd]

I used to clean the grate on my old 18" kettle by filling the body of the grill with balled-up sheets of newspaper, putting the grate on upside down, and lighting. When all the crud had burned down to ash and the grate was cool I would then brush it with a brass wire brush, then give it a light coating of cooking oil. That seemed to work pretty well.