I am trying homemade traps with a funnel made from a paper plate mounted on top of a giant peanut butter jar but it is only catching a few.
I'm going to pick up some 
glue boards and bait them. I've got high hopes.
I was once waiting at a deli counter on Long Island. It was an Italian deli and there were about a dozen other people clustered around the glass case.
They had all kinds of imported salami and cheeses hanging from the ceiling.
Right in the middle was one of these 
hanging glue ribbons for flies.
That fly tape was standing room only. They were three flies deep all over it. There was not a speck of the yellow tape showing anywhere. I felt like all of us were mesmerized by it.
It was my turn to order. I said; "Let me have a half a pound of roast beast. A half pound of Provolone ..." I then paused for a moment before adding; "And I'll take a quarter pound of the flies."
The room erupted.