Old typewriters --- whether they work or not --- provide an attractive accent piece for a writer's office or can be mined for parts, such as keys. If you've found an old typewriter in your basement or attic, take a few minutes to make some phone calls rather than throwing it out in the trash. Putting an old typewriter in a landfill creates waste, so choose a greener option.
Call typewriter repair shops near you to see whether they might want your old typewriters for display or for parts. If the typewriter works, this is a good option. You can also contact vintage stores or antique stores that might have resale interest in your old typewriter, even if it's just for decoration.
Post an advertisement for a free typewriter on recycling networks like Freecycle or Craigslist (see Resources) if it still works and you can't a typewriter repair shop near you. Describe the make, model and approximate age and condition of the typewriter, and provide an e-mail address or telephone number so interested parties can contact you.
Call your town's Department of Public Works and ask whether they have an electronics recycling program or an electronic waste drive coming up. These events allow you to dispose of electronic waste such as old typewriters in an environmentally responsible manner. Dispose of the item on the appropriate day if it's a one-day event or bring the old typewriter to a drop-off location.
Non-electric typewriters can be disposed of in the trash as a last resort, but electric typewriters cannot legally be put in the trash, since they are considered electronic waste.