Originally Posted by 5picker
That seems like an odd couple of things that would be trying to get past the upper slide seal wiper.
Its a term commonly used in the automotive circles defining certain air filters.
"its a B&R filter, designed to keep out birds and rocks".
My Arctic Fox slide seals used to do this on the sides all the time. Spray-on seal conditioner helped some, so did waxing the side of the slide. I could put it all the way out, then bring it in some, then go out again and it seemed to go away until next time.