Unfortunately, I am a hoarder. I currently have three twenty ball racks of a mixture of old and new balls. But that being said, there is always a condition that may pop up in a tournament or league where that old "has-been" will suddenly become very useful again! So no, I don't arbitrarily just get rid of old stuff.
Old stuff listing: Black, Blue, Burgundy and Red Hammers. Lime Green Messenger and Three Purple Ninjas. One Wolf and an EBO Savage.
I have used a couple of the Hammers and the Ninjas just this year in league play on a light oil, spotty shot.