I have used the smoke sticks you buy that burn like the punks you used to use to light firecrackers with. I have found them to be perhaps the best cover scent available. I have had deer walk in a 360 degree circle around me, while sitting in a cedar bush, and they were no more than 5' away and either never knew I was there or did not care. I made myself a smoke can with two coffee cans. Drilled holes in them and fixed one to fit over the other one. I just sit it a few feet down wind of me and the smoke sticks last about one to two hours.
Louis