I've heard of vanilla being used as an early season attractant / curiosity scent, but never as a cover scent. I think the idea is to use like you would a doe-in-heat scent or something like that. Put canisters out at 20-30yds. I tried it many years ago and got NO reaction whatsoever.

Now I just go as scent free as possible and don't give the deer anything strong to smell that might make them try to smell me! I don't believe cover scents can work anyway because deer can easily distinguish many scents at the same time.

... Shockwave