I find a LOT of fans on the curb, a large number simply need to be cleaned to work, others may need a screw or some creative thinking. Sorry for the lack of step by step pics, the idea hit me and was finished before I even thought of pictures
Step 1: The Light Bulb Flashed
I picked up this small pedestal fan the other night, I plugged it in and it worked fine but it was missing 2 feet, then I noticed a base for an office chair I had rescued a while ago and it looked to me like the base would fit the hole
Step 2: It Fit
a couple of twists removed the fan and its pole from the broken base, the base then went right through the hole in the chair base, I marked it where it stopped and cut the fan base, added some hot glue for security and shoved it home. A little more hot glue filled the space (about an 1/8") around the top and then reattached the fan pole.
What you find may need other simple repairs or may end up back on the scrap pile
Step 3: Box Fan
I found this box fan the same night, it was dirty and didn't have any screws for one side, a quick cleaning and a scrounge through my parts box and viola...
I guess it depends on how you define treasure but on a 90f+ day 2 fans sure came in handy, I kept them from a landfill for a while longer and best of all kept $30.us ? in my pocket...
Your experiences may vary depending on what you find