I wanted to get rid of the Drakkin on my server. I left (or re-did rather) the character point allocations. If they exist it's not a problem (that I know of), I left them there because when I tried to create a race/class combo with no point allocation it crashed my server.
I simply deleted the character class combinations for Drakkins and now when you click on them in the character creation windows it does nothing.
As far as removing class/race combinations from live I'm not sure. I only added classes.
My best recommendation is get Navicat Lite. I found it online, it's legal and free and while not all of the functionality is there it still works like a charm and puts everything into a spreadsheet for you so it's easy to just delete lines and create new ones without ripping your hair out trying to figure out commands my MySQL.
Also another tool that is AMAZING is
http://eoc.akkadius.com/AC/eoc/login.php
It took me a while to get it working because of port forwarding issues and MySQL user permissions but now that it's up it really is a life saver.
Hope that helped. I know what a headache it is to try to figure it out but the people on the forums helped me out a lot.