If you have a humidor (supplied with each #58 cartridge) you could use that.
Otherwise the best bet would be to put it in a Tupperware sandwich container
oriented so that the nozzles will not touch anything. Put folded piece of damp
paper towel in the box and then seal it shut and keep it in a cool place. Do
not put tape (or anything else) on the nozzles as it will likely cause color
mixing, ruining the cartridge.
Regards,
Bob Headrick, not speaking for my employer HP