I have been using the old (gold color) listerine mouth wash as a fly spray. I have it in two different bottles. One bottle has only the listerine in it and I spray it on my self, the horse, saddle and everywhere. The second bottle, I put fly spray in it and some listerine. When I am not riding I use this to help keep the ticks, flies, and mosquitoes away.
The stuff by its self works for keeping the mosquitoes and flies away good.