Is there a way to remove all old users from the database that either don't have validated emails, or who have never signed in? We have a few thousand of these accounts.

Hopefully there is a board control panel feature to do this. However, I am proficient in MySQl, if that is the only way to manually remove the accounts. I just want to make sure I don't remove a bunch of users and then break the boards.

When I run this query, I get over 20,000 rows in response, which indicates there are a lot of sign-ups that are invalid.

Code
SELECT USER_REGISTRATION_EMAIL,USER_LAST_IP,
USER_REGISTERED_ON,USER_LAST_VISIT_TIME,
USER_LAST_IP 
FROM (ubbt_USERS as u, ubbt_USER_DATA as ud) 
WHERE u.USER_ID=ud.USER_ID 
AND USER_RULES_ACCEPTED=0 
AND USER_REGISTERED_ON=USER_LAST_VISIT_TIME 
AND USER_LAST_IP IS NULL 
AND USER_LAST_IP IS NULL;

For those users can I simply do something like this, perhaps with throwing in a check to ensure I only run this on users over 10 days old? Do other tables need cleansing as well?

Code
DELETE FROM ubbt_USERS, ubbt_USER_DATA
WHERE ubbt_USERS.USER_ID=ubbt_USER_DATA.USER_ID 
AND USER_RULES_ACCEPTED=0 
AND USER_REGISTERED_ON=USER_LAST_VISIT_TIME 
AND USER_LAST_IP IS NULL 
AND USER_LAST_IP IS NULL

Many thanks.