I use head cement on all my flies and still catch large numbers of bass, brim and even the all time champion of scent detection, catfish. 90% if my fishing is still water so there is no current to whisk away offensive odor. I just don't believe that most fish are that bothered by head cement and other glues once they have cured for a couple of days. I make a real effort to keep my flies free of gasoline, oil, bug dope and sun screen. I do try to find some rock slime or lake mud to rub on new flies before I use them. Just my 2% of a dollar. I'm sure others will disagree. 8T