A hard reset, also known as a Powerwash, on your Acer Chromebook will restore it to its factory default settings, essentially making it like new out of the box. Here's how you do it:
The reference video states "your Chromebook will begin the Powerwash process [and] it may take a few minutes and once it's finished you'll be able to set your Chromebook back up again as if it was new out of the box."