As an ex-trapper, I understand scents and keeping equipment clean but when it comes to calling I think we over-think this. Callers are a hard surface, we don't interact with a caller very much(exposing them to our scent) so they aren't major sources of scent, a coyote has to be quite close to even know it is there. I've had coyotes jump up in brush and grab callers and pull them down, walk up and stare at the caller trying to figure out the sound, circle callers at a few yards and just trot off. I run my decoys elevated and have had two coyotes leap four feet in the air and grab them.
I think the scent factor on a caller or decoy is such a minimal factor that the time dealing with it would be better spent putting in more stands or finding stands more stands to hunt.
I do understand the confidence factor in hunting. If a person thinks something works for them it will and changing things will put them off their game.
