During a hatch? I'll swap it around til I find th eone that works, then its got Mojo and shall not be touched until it snaps off. Then there will be anger, for no matter how much a clone I may have, it is not The Magic Fly. I will procede to begin frustration, swapping flies every 10 minutes or 2 casts, whichever happens first, until I either go home in tears or I find another Magic Fly.
Lather. Rinse. Repeat.
But, if I've got one that works, it stays on. If it becomes destroyed to the point where it no longer works, I will clip it off for one near 'nuff to it. Often times, I'll just squeeze the gunk out iwth my shirt, dump cold cream on it to float it, and then re-cast.