its hard to say because the compounds they used to make the liquid clen have many different exp. Usually a vial containing a medication will have a shelf life of 3-5 years with out being open,once its been open its usually gets 1 month to 6 months of exp.
But lets say its over a month of its expiration, you could still use it but It wont be as effective. But thats only for orals. If its an injectable and its past its exp than that something you throw away because of the chances of bacteria building up. But thats another story.