Keep it covered
Dust is the number one enemy of a typewriter. Use a cover or case whenever the machine is not in use, even overnight.
Brush, do not spray
A soft brush removes eraser crumbs and paper dust from the segment and around the typebars. Never spray household lubricants like WD-40 into a typewriter; they gum up and attract dirt.
Clean the type
Use a stiff brush or a bit of putty-style cleaner on the type slugs when letters like e, a, and o start printing filled in.
Change ribbons before they fade
A ribbon that prints gray is done. Waiting only makes you strike harder, which wears the machine.
Release the tension when storing
For long storage, leave the carriage centered, release the paper bail, and store in a dry, temperature-stable room, never an attic or garage.
A few minutes of care each month can extend the interval between shop visits by years. When something feels wrong, stop and call rather than forcing it. Related service: Electric Typewriter Repair.