Horse Fly Control- No Spray?

My senior horse is deathly afraid of spray fly repellent, he was bitten by a dog while getting fly sprayed before I got him so now you can't go near him with a bottle.. I usually have to get the jugs and douse a cloth with the repellent and rub him down. I don't mind doing this for him but if there's an easier way, I'd love to hear it! Thank you!!