RPCookin
Executive Chef
I have no problem leaving my grill dirty until the next time I use it. Then I turn it on full blast to pre-heat and walk away. 10-15 minutes later any food residue is ash and I just brush it off. Then I oil before cooking.
A guy here who is a hog raiser also has a cooker on wheels that he takes to many pig roasts each year. He never cleans the grates until the day before an event. That keeps the cooking surface well oiled for rust prevention. He will fire it up the day before and burn off any residue from the previous outing. He's been doing that for some 40 years.