The Q-Jet white is "Fast White", a different formulation than WL. Time will tell how they oxidize and or swell. I've tried to fly old WL RMS motors that were swelled shut, by filing a new slot. Problem was, they chuffed far too much off the pad, causing 1 or 2 problems. First, they might come up to pressure only after off the rod/rail. Second, the delay might start right away, and might burn through right when the motor gets the rocket up to speed. If I come across those in my stash now, they get tossed in the fire pit, for some brief entertainment. I really try to cycle through my reloads, and with WL, only buy what I'm likely to use in a flying season.