Once when my late Landscape Architect hubby wanted to
re-landscape out back yard, he yanked out my big bed of mint
that I loved. Suddenly the flies came in droves to join me in the
kitchen and all over the house. With Dobermans and kids by the
dozen running around, it was horrid. So I replanted a huge pot of
mint and put it beside the back door. That kept most of the horrid
things out, but not all. Grandma back in the hills used to plant mint
around the barn to keep the flies down somewhat, and we both
love Preying Mantis for fly catchers delux!
Hubby's sweet old Portuguese mother told me to paint the under
side of the porch roof blue. That back in Portugal her family could
not afford screens in the early 1900s, so painted whole houses
blue to protect them from flies. It did work some, worth painting
it and it looked nice.
For inside windows, I hate to wipe up smashed flies, so use a
Dust Buster for catching them. Cleaning out the bag isn't so bad
wearing rubber gloves.