Follow ZDNET: Add us as a preferred source on Google. Every new Google email account comes with 15GB of free storage -- a solid offer at no cost. However, that space can fill up fast, especially since it also covers files in Google Drive and Google Photos. If your inbox is cluttered with unread newsletters and sneaky spam, there's a way to clean house without losing important messages. With the right approach, you can preserve what matters while giving yourself a fresh start. Also: Google Maps just got its 'biggest update in over a decade' - it may change your driving for good There is always the option of manually cleaning your Gmail inbox or downloading content to your local drive. What a pain, though, right? And, chances are, you'll only eliminate so much junk before those gigabytes start stacking up again. I should note that Google offers a way to pay for more storage by upgrading to a Google One account. The "Basic" plan costs $24 per year for 100GB.…