Finding mouse droppings in a grill at the end of the dormant season is not uncommon. Rodents are able to get most anywhere. Their keen sense of smell will guide them to any charred or caked-on fat or food particles left clinging to your grill in storage. To sanitize your grill and make it safe to eat on again, you must clean and disinfect the grill and the parts. It's a messy job, so give yourself plenty of room to work.
Take the grill apart following the manufacturer's instructions for disassembly.
Scrape off burned and caked-on debris, rat feces, hair and other detritus from the grill, burning grates, heat shields and valves, using the putty scraper and wire brush.
Hose down the grill parts to remove any clinging debris.
Spray a degreaser onto the grill and its parts according to the degreaser manufacturer's instructions. Allow the degreaser to sit for the recommended time. Scrub and wipe the grill and parts clean, using the scrubbing sponge, wire brush and paper towels.
Hose down the grill parts to remove any clinging degreaser.
Mix a solution of 1 gallon of soapy water and 1/4 cup of white vinegar in a bucket. Wash the grill and the parts with the scrub brush dipped in the solution.
Hose down the grill to rinse away any soapy residue.
Wipe the grill down with a lint-free towel.