A few years back on a fishing holiday in Slovenia we ran into the problem of not having enough of the flies that were catching. Limited to just a few of each, it was a case of once waterlogged - remove, dry and replace with another. We used conventional fly patches as we were traveling light. But what I imagine has been the case for so many of you, happened to us, we began losing flies from the patches (especially when using barbless flies). This bought with it all types of problems as our few 'catchers’ were now less.