Q: Eliminate devices from my account

They are on your account in what way ? If they are associated to your account then you can log into your account on your computer's iTunes via the Store > View Account menu option and remove the association (assuming that they've been associated for 90+ days) : iTunes Store: Associating a device or computer to your Apple ID

If you want to log them out of your account then you will need to do so directly on them by tapping on your id in Settings > iTunes & App Store