check the eyes too, rust is abrasive and abrasive+fish on = SNAP! and bad language. . . try that sandpaper ( 1000 grit is my vote as it gives the hook point a nice polish ) and test the strength of the bend with a pull or two.
not to monday morning quarterback you, but, I carry a small box of flies and have a back up box with the majority of my flies I call the 'shop' somewhere accessable ( in camp, the car, with my lunch etc.). there's no telling when your gonna step on a rock weird and have your stash flip out of a pocket and watch it swiftly float downstream, quickly ending your day if 'all your eggs are in one basket'. . .
if you have to toss your flies, do it and don't feel to bad about it, equipment failure is the absolute worst way to lose that fish you've been after for years. . .
good luck, tight lines