I torch and brush the grates after every cook. Every few cooks, I remove the grates and power wash them (no soap). That's when I scrape out and hose the bottom of the smoke chamber. I remove the ashes from the fire chamber after every cook. Not only does it keep the bottom from rotting out, it also keeps the air flowing well and give me consistent temperatures throughout every cook.
Mister Bob, Pitmaster - Bob's Hogs. KCBS CBJ #31759 - IMBAS Certified MOINK Baller