Oil bath air breathers have been around for a hundred years for a reason... they work. I have 4 tractors dating from the 40's through the 60's that have worked through the most brutally dusty conditions one can imagine. No air related failures. We just rinsed out the hog hair yearly and serviced the sump as needed. Scraped out about an inch of dirt and bugs and topped off with motor oil.
Now, with the almost sterile conditions a Stovebolt operates in today, wash the hog hair with solvent, oil it and forget it. Then simply clean the crud out of the sump and fill to the line with each oil change.
I don't like using compressed air. Tends to break up some of the hog hair. Just let it dry in the sun. Then oil it. Overfill and the carb will suck it in. My 54 3100 likes it just below the fill line.
