I think the hardest part is removing all the plastic fasteners that hold the sound deadening pad to the underside of the hood in a way that allows them to be reused. There are tools made especially for the job, although a couple of well placed screwdrivers will do the trick too.
Trim removal tool
You can usually buy both the trim removal tool, and replacement fasteners (if necessary) for not much $$$, at most places like Autozone..
Once that pad is removed, a simple socket and ratchet is all you need to take off the insert.