Storing cartridges

I sent back my first 4900 this week and removed several refillable carts and wonder the best way to store them. I put the vent plugs back in but is there anything else I should do?, also the refurbished replacement I received does not work so they are sending out the third one(maybe the third time is a charm) the OEM carts were in the second one for a few hours so can I also save them and reuse them after the carts with the third one is gone, providing it works? I am not usually an advocate for extended warranties but in this case I am pretty sure it is on my list of things to get.