u/Aquarian76

I have 2 half-used Snow Peak Giga Power canisters that have been sitting for quite a long several years. They might even be older than 6 years not sure. One has original cap on it and the other does not.

I'm going out in a couple days and decided to test the one with the missing cap. Upon unscrewing from my stove, the canister valve stayed open, causing a high & fast leak. I let it leak out in the backyard.

1. If that happened to me out in the field, what is the proper procedure to save the fuel when discovering the can's valve now faulty, wont close? Should I be screwing it back onto the stove and hope for the best? Assuming that the stove's valve will save a faulty canister valve?
2. Should I also test the other old can (had cap on it) or just replace both of them with new ones. I think after 6 years maybe fuel has degraded?
3. What brand or type of fuel is best for the Firemaple Stove? (Jetboil's budget competitor) It's strictly for boiling water nothing else. Spring-summer time, desert heat at night, is there certain type of fuel better suited for that?
4. How or where to dispose of old canisters both full and used?