guess I was lucky on cleaning the air filter on my old TO-35, 1957 model.
I always kept the air filter oil bath clean and also ran a stick and cloth up the air tube and kept it clean,
but then one day, read on this site about cleaning out the air filter wire mesh.
I took off the air cleaner and placed it in a 5 gal bucket, then filled the bucket with kerosene and let it soak for a couple of days.
then poured out the dirty kerosene, rinsed out the wire mesh a few times with clean kerosene, until the fresh kerosene ran clean after rinsing out the filter.
Then let the air filter air and drip dry for a few days. to be sure the air filter wire mesh was dry.
replaced the air filter and filled the pan with oil, works fine.
but man-o-man that wire mesh was full of dirt, probably the first time the wire mesh air filter had ever been cleaned as we have owned the tractor almost since new.
I guess I just never thought about cleaning the dirt out of the wire mesh filter housing.