Delete own data (after development/testing)

I have been testing a site and now have Piwik showing all of my test page views/actions. I want to delete all of my own data but nobody elses. In amongst my own data will be real user data so I want to keep that intact.

All of my test data should be tracked on the same IP, so is there a way to delete data for a specific IP? Or even just delete data for an IP that was tracked on a specific date?

I appreciate this will need to be done directly on the DB.