Old URL successfully redirected for over a year, no longer need it.

Changed the URL of my Wordpress blog a year ago. The old website’s wordpress files and config files remained on my Droplet all the while. No I want to get rid of everything to do with the old URL on my droplet, which includes ending the redirect, removing the URL from DO nameservers, etc.

Can someone please guide me in terms of what to do first, second, etc.? Any words of advice would be appreciated for the absolute novice writing these words.

Thank you very much for your time