I have some Aerotech AP reloads (nothing over "F") that are about 8 years old. Junk? I may donate them to the local Tripoli club in San Diego if they are still useable. Also a bunch of estes BP engines which I'll probably soak in water. Dave B.
Estes motors (BP) can last FOREVER if stored properly (no extreme temperature cycles - and you should fire them at a temperature less than 75 degrees F below the highest temperature they ever experienced).
Aerotech motors can sometimes develop a crust on the exposed propellant surface. A seriously dipped Magnelite will burn through the crust - just make sure it is dipped the entire length of the core with ignition starting at the top.
They should be fine, as long as they've been stored reasonably well. (No water damage, etc.) The grains may have developed some white crust or spots, but that won't affect use. Just brush it out of the core so it won't interfere with ignition.