As an unfavorable alternative: This might be more of a hassle than you'd like, but have you considered rebooting the device after heavy use sessions to terminate unwanted apps in the background?
I need a basic tip for closing apps when not in use. I'll get Pandora in my pocket sometimes, days after using it. I know the hold and wait till they shake for deleting, but I don't think that is my solution. Any tips?

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