Q: How to remove previous Apple TV's from Airplay list on your iPhone 6?

I replaced two of four AppleTV units today. The new devices installed without a hitch and are humming along. They show up in Airplay, so all is well...almost. Does anyone know how to knock the old Apple TV devices off my Airplay list in iTunes?

What I've tried:

Restarting iTunes

Rebooting my iMac

Rebooting my Airport Extreme

Investigating options in iTunes preferences / devices

Hunting around in the Airport Utility for anything that might help

Looking in "sharing" also for anything that might make sense

A little side note:

It's not a big deal. Everything works fine. It's just annoying