Sorry to disagree with all you posters but if you remove the cartridges from the printer you take the chance of killing the cartridges AND the print heads. I have experience with this and i can tell you for certain that leaving the cartridges IN the printer is best for long term storage.
I have taken printers out of storage after 2 years of storage and as long as the cartridges were still installed they worked just fine the first time. The printers that I had to spend days unclogging were the printers that had no cartridges installed even though the ink resouvours were covered.