Hi Joyce and welcome!! You have certainly come to the right place as we are all about all things asthma and asthma related.
The correct answer to your question is, once a medication has expired, it should no longer be used. However, you should be aware there is a lot of discussion surrounding this very topic. There are folks in this community who subscribe to that proper answer. Still some community members have shared that, even though they realize the medication is no longer recommended for use, they continue to use it.
I thought you might find it interesting to look over these two articles which focus on asthma medication expiration dates. First this one, on the truth about expiration dates: https://asthma.net/living/the-truth-about-medication-expiration-dates. And, next, this article, on rescue inhalers and expiration dates: https://asthma.net/clinical/rescue-inhalers-for-asthma-can-you-use-them-after-their-expiration-date.
Clearly, we cannot advise you whether the medication canisters you have at home are safe to use. This is a decision and a choice you will have to make yourself. You may want to discuss the topic with your prescribing physician and or your dispensing pharmacist.
What do you think?
Leon (site moderator asthma.net)