Assuming you are using the WordPress one-click image you can remove wordpress by taking a couple quick steps:

1.) Remove your web files:

rm -Rf /var/www/html/*

2.) Remove your database. First grab the mysql root password (this is shown in the MOTD shown when you log in via ssh).

mysql -uroot -p

you will be prompted for the password and after entering it you’ll be at a mysql client prompt

DROP DATABASE wordpress;

then you can close the mysql client with

exit;

One thing I feel I should note. If you create a droplet without an ssh key, the password emailed to you is your SSH password for the root user only. It is not used for anything else. That password is temporary and you must log in via ssh once to change it and to complete the WordPress setup (this is to prevent a new WordPress droplet from being susceptible to hijacking before you set it up).

I just went to destroy droplet and rebuilt it to the base settings.