Printers, which are primarily mechanical, should also be cleaned on a regular basis. With each sheet of paper that goes through the printer, there is left behind a small amount of paper dust. This is hard to see, but deadly to the printer. This is not just for your safety, but also for the safety of the system. A trickle of DC won't affect you.
Cleanliness extends to the storage media.
That tiny fleck of dust that is just barely visible to you can gouge a diskette or tape. The key is to keep all diskettes and tapes properly stored. This means, keep them in their jackets when not in use, and stored inside a storage box. You can go just so far with keeping diskettes and tapes clean. To cite an example of this, another friend had a child drop a peanut butter and jelly sandwich onto a diskette.