You can remove the contents of your Google Merchant Center account by removing your data feeds and your Website URL from the Settings page.
Note: If after removing your Website URL, you'd like to register it in a new account, it may take up to an hour before you're able to do so. You will also need to verify and claim the website URL in the new account.
You can also permanently delete your Google Account that's associated with the Google Merchant Center. Learn more