I'm in the same situation, the Yugo ammo I have has a lot of duds and needs a lot of second strikes. I pulled the projectiles, but tossed the powder.
I honestly, I debated about it, too. The powder didn't seem to show any signs of age, but I figured better to be safe than sorry. Tough call, though, I could see it going either way. Maybe next time I'll reduce the charge and reuse the powder...