My advice is to keep them in their native environment. Glass jar full of gasoline.
Even the injectors at FIE start to have problems with 'preservative' injected through them. This is USED rebuilt injectors. Over time, they occasionally get unhappy. This is why FIE re-flows injectors previously flowed to verify they still work and flow the same when a new match request comes in.
Once running, they're fine. Fill a jar with gas (enough to cover them), with a gas-tight lid, and flip it upside down ever few days to help burp the air pockets out. They should last forever that way if they were still good to begin with.