So I used to use CD-R(W)'s as backups, but then I found the joys of DVD-Rs, which can back up my entire hard drive at once, so I stopped. (Then the burning process stopped working, but that’s neither here nor there.)
I still have a bunch of unused CD-R(W)'s. Anything I can do with them before I just chuck them all? No garden, so no reason to hang them up anywhere.
You could make them into some kind of art thing with them. Hang them up with some fishing on a wire hanger, a dash of paint perhaps as well. Sell your creations at a local hippy market or etsy or some such.
On the opposite end, you could take them down to a shooting range and blast 'em with a shotgun. That could be fun too!
A friend of mine who runs a music magazine gets HUNDREDS of promos through, and the vast majority of them end up in the bin. Because of the toxic chemicals in them, they are not good to be chucked into landfill. I believe a company actually picks them up FOC because he gets so many, so there must be an incentive for them there somewhere. Perhaps find someone else locally who has also stacks of discs and get rid of them responsibly together.
I use CDs for backing up projects that aren’t big enough to need DVDs or bigger backup hardware. A single CD holds an awful lot of text files, for example. A CD easily holds all of the photos I take in a month. Why use more expensive DVDs if 90% of the space is wasted?