About once a week I blast out everywhere I can with compressed air. It stays pretty clean. Any thing that does get in gets chopped up by the fan.
It does burn about a quart of oil between changes.
I am cutting knee high tumble weeds.
A little bit less invasive thing I could try is put a 12 inch fan fan on the hood and force more air over the engine and in the engine bay. Might try that first. I have a fan laying around, fuses, breakers, switches, wire in my junk collection. I guess if the magneto can keep up with the fan it could work.