I have a couple jugs of hydrochloric acid I use for my pool, and they seem to offgas hydrogen chloride all the time.
I noticed that in the cabinet where I kept them, all the metal fittings are rusted. I held a piece of litmus paper near the cap of the bottle (but not touching it) and it slowly turned red.
How do I keep it from offgassing? If I put it in another airtight container, would that be safe, or would the lid eventually shoot off from the building pressure?

How do people in chemistry labs store it?