Simpson 63G904S / 63G904W

Service problems Gas cooktop 63G904S – We find the spill tray convenient for everyday cleaning of the cook top after use, good design by Simpson for 3G904S; however the problems crop up when we do not have such a tray or access to clean around the control knobs/ regulators. Are we meant to leave it for service technician to clean the grimy dirt gathering around and below the knobs works so far ok difficult to clean at the bottom of control knobs and hence develops problems requiring gas plumbers.