I cut the RFI Ferrite blobs off of all trash Keyboards and stuff. These are great Ferrite devices.
But what are they best for?
Bob,
Check out this article from Chuck Councilman W1HIS:
http://www.yccc.org/Articles/W1HIS/CommonModeChokesW1HIS2006Apr06.pdf
He wrote it from the perspective of an HF operator, but there is a lot of useful information in it.
Chuck is fairly generous with his time, contact me off list if you want his e-mail address.
In my personal experience, equipment vendors are mostly required to test at >30MHz, so it would not surprise me if the pieces you pull off discarded equipment are well suited to VHF/UHF. Since the article was written, ferrite has become easier to obtain in small quantities. Mouser has worked for me - it might be easiest to buy exactly what you need rather than experiment with with whatever the junk box provides.
But sorting through junk boxes is fun too!
-Joe KM1P