I remember a time ...
When as a PFY, I was handed a bottle of iso-prop, a toothbrush & a jewellers screwdriver to clean a second hand DEC drum printer we had acquired second hand.
My job was to use said toothbrush, jewellers screwdriver & iso-prop to clean the decade old remnants of printer ribbon & paper dust that had caked up the print drum to the point where it only printed letter-ish smudges.
I emerged many hours later from the computer hall looking very much like a giant smurf; but the printer was sparkly clean & worked a treat :)