Can I Store Left Over Fireworks? We get this question  at AllSparkFireworks.com quite frequently and it is a smart, safe firework enthusiast who asks for advice rather than making assumptions which could be wrong. If you bought too many fireworks for your celebration or were not able to light them off, check out our tips for storing fireworks:
Check with local laws. While in general, fireworks can be stored from one year to the next, and even longer since the chemical properties don’t change over time. However, it may be illegal in some locations to store fireworks outside of specific holiday dates. Always check with your state, city and local ordinances, rules can even vary from one housing subdivision to the next.
Keep them dry.  Do not allow fireworks to come into contact with water. Water damaged fireworks can misfire or explode, never try to dry these fireworks out and then relight.  Even excess moisture from the air can cause exposed fuses to become not lightable. In high-humidity areas, store fireworks in a sealed box with a package of silica gel desiccant
Do not jostle.  Overly disturbing stored fireworks can cause contents within the items to become loose and not work properly. For example, the engines of rockets and missiles have a hollow cone-shaped area and if it is bent or broke, the rocket won’t fly. Roman candles that have been bent may cause stars to explode out of the sides, you get the idea!