Resolve carpet foam as grout cleaner: Spray it on. Leave for 10 min. Scrub it off with a stiff scrub brush. Tip: as you scrub wipe the dirt that comes up off. If you don't it will just soak back in before you get back to mop it off.
Around our place there is no such thing as a 'Fly Free Season' . Build the Cadillac of Fly Traps for a Fly-Free Summer says if getting this many flies- a good clean up of old bedding etc may be needed as well