I'm almost wondering if a fan pointed at the back of the unit would help? I mean, with a metal back, it should be one giant heatsink, so forcing air circulation over it should help; it may not be much, but something is better than nothing.
I think the suggestion by @Golfdriver97 is a really good one. Also, welcome to iMore. You may want to consider signing up for an account here on iMore. That way it's easier to connect when you have specific questions. If you're interested, click here to learn how to sign up!