So here we are, offering several ideas for your to help your dear grill away from those mouse.
I won’t tell you how to clean your grill as it’s obviously something you should do at the first place.
The very first option is use steel wool/woven wire/wire mesh/Sheet metal to fill the grease opening tube, it’s a very cheap, easy and effectable way, but there’s also some inconvenience, you have to put and take off it every time between grilling.
The second way is wrap aluminum foil around the smoke stack and grease drip spout, just make sure you aluminum foil is solid enough and also, you have to remove them every time grilling.
The easiest way to do it’s put some Fresh Cab Rodent Repellent around your grill, it’s something amazing and non-toxic but strong effect to keep rats away.
And please remind that Dryer Sheets Don't Deter Mice, it may works for a while and it couldn’t stop mice once they try it.