You need a more systematic approach.
Step 1 is to fire up the video camera. Pix or it didn't happen.
Step 2 is gently approach, and hook some ropes to the cover with spring clamps. Loop rope over tree branch, and retreat 30 feet or so.
Step 3 is get long shopvac hose, and the oldest, most-polluting car you have.
Step 4 is connect hose to exhaust, insert hose into bottom vent opening, and start car.
Setp 5 is have the obligatory 11 AM beer. (Hey, it's your day off, why not?)
Step 6 is let car run for 30 minutes, depleting oxygen in grill.
Step 7 is approach grill, hook up tank (just in case) and retreat.
Step 8 is have assistant raise cover with rope mechanism, whilst standing guard with two cans of nasty spray for protection.
Step 9 if coast is clear, use a broom to open lid of grill to survey the carnage... spray cans at the ready.
Step 10 is fire up grill to toast any remaining sleepy bugs 'til waspicide is complete.
Step 11 is let things cool, bag the carcasses, and post the youtube video if anything didn't go per plan...
Or... toss in a few leftover M80s.
Chip