With scatterbait it's made to be broadcast/spread on the ground or floor, but it makes a good attractant/fly killer in a flytrap. A Big Stinky is a gallon jar with a top on it that you put an emulsion in that attracts the flys and they can;t get out. Take a 2 liter coke bottle and cut the top off at the top of the label. Turn the top over and push it inside the lower part so that it looks like a funel into the bottom. I just use a piece of hot wire to make a couple of holes near the top of the contraption and stick baling wire though the holes and hang it up. Throw some scatterbait inside (through the funnel looking top) and it will start catching/killing flys in just a few minutes. If you have a big area, make sevral. You can freshen the scatterbait or just burn the whole deal and make a new one.
Golden Malrin is one scatterbait, but there are dozens (at least) of them.