Inspect your old 8mm projector. Make sure the unit is operational and does not have any parts missing. A projector that is still in working order is much more likely to sell than one that in currently inoperable, plus it is likely to bring a better price.
Make a list of any accessories you have on hand. This can include film cans and carrying cases. Extra lenses and bulbs will also add to the value of your offering. Include every accessory you have, no matter how inconsequential you think it may be.
Draft the basic content of your ad. Use the word processing program on your computer or simply work up a rough draft using a pencil and paper. The idea is to create a template for your ad that will translate into several different advertising outlets.
Set your price for the projector. Keep in mind that you do have a specialty item, but there is a limited market for it. Determine a price you would like to get for the projector along with a price you will settle for if necessary.
Take out local print advertisements. This will include your local newspaper along with any local free classified publications. You can use the same ad on index cards and post them on the bulletin boards at local supermarkets and laundromats as well.
Make use of online advertising as well. This includes local online classified message boards and auction sites. Possible buyers who never read a newspaper could very well spot your ad if posted online.