I think it has to do more about concentrations. The stick had a high concentration, ie, freshly handled. Scent concentrations diminish over time, therefore are less concentrated. I think deer know how fresh scent is by its concentration on a molecular level. If you wear a shirt one day it will have a certain amount of scent, wear it two days in a row( you get my drift). If you wash that shirt properly we're right back to square one. Now if you just hung that shirt out to air out, over time the scent that you initially deposited on that shirt would dissipate and at some time it would again be scent free.