Has anyone blocked off their cowl opening?

[AMC1]

After the PO of one my eagles did some serious engine restoration the car sat for 10 years. I noticed cottonwood or whatever seeds in the outside top vent - the kind that look like a helicopter blade when they fall. When I later removed the dash I couldn't believe the hundreds more I found inside. Once they get in the outside the moving air later forces them down inside the car. It can't be good for heating/cooling.

[casper]

That cowl area is a high pressure area. The air actually spins backwards at the bottom of the windshield. Hints the reason cowl induction hood scoops work very well. Air is actually forced into the hood scoop from the windshield. I would go for a piece of marine vinyl, with wide seams on the edges with magnets in place to cover the cowl opening, and be removeable easily.

[madmax4x4]

I'm trying to come up with something to do with mine. I have water pouring in the driverside floor in from the cabin air port. The one with the push pull know. To it to the car wash last night and that's when I found out where it was coming from. What would cause this?

[carnuck]

Rust under the cowl or totally clogged with pine needles like mine was. I used a leaf blower to flush all the needles out after wasting 2 hours trying to do it with 1 arm (right arm was in a sling after surgery to reinsert it in my shoulder socket) Did that right before I replaced the heater core (also one armed)