The house used to be a rental, a couple bought it and have been slowly fixing it up.
Suction line freezing, not much airflow, so I did some exploratory surgery.
I thought how in the heck did this hair sweater get sucked up into the coil?
Guess for years, the dog laid on the return air, (in the floor) and the tenants never had a filter in it. I stuck my filter brush under one corner, it lifted off in one gross slab.