Yeah, I won't put anything on it.FB is almost impossible to prevent at certain temps.
Ventilation can help, and essential for air quality, but it's no guarantee against FB.
No kind of 'goop' will prevent or cure FB, best to leave it be.
I'm pretty confident of adequate ventilation in my coop. During the day, I probably have 15-20 sf open. At night, it's more like 8-10 (for 7 birds). The most I ever smell is occasionally a fresh cecal poop in the morning when I open the door. I use smell as my gauge for ventilation.