If it's that old, particularly if identifying information is not able to be read, you should contact a chemical disposal expert and just get rid of it. Don't try to dispose of chemicals yourself if you don't know how. For one thing, it can be dangerous. For another, there are a lot of laws governing disposal of chemicals. If you don't know who to call, first try your local waste disposal company (usually found at your local administration webpage); they can probably point you in the right direction if you explain the situation. You might consider getting rid of the corrosive storage unit as well - new ones aren't that expensive.
Corrosives, oxidizers and flammables should be stored separately in appropriately rated storage cabinets. Peroxide forming chemicals (e.g., ethers, THF) should also not be kept indefinitely. "Poisons" is a rather vague term, not sure what you mean by that. Unless the substance is particularly toxic, usually you don't have to treat it in a special way, although it is customary to store inorganics separately from organics.