How to remove your Scratch account
1. Go to http://scratch.mit.edu/api/getinfobyusername/
After the / fill in your username. Find the numbers and copy them.
2. Navigate to http://scratch.mit.edu/users/close_account/
After the final / type in the numbers your account is closed.
(Thanks to Ed.)
Helpful Trick: Removing online data
Helpful Trick: Remove third-party logins
If you signed up for Scratch using a third-party login such as Facebook or Twitter, you probably want to revoke all access from Scratch. Click here to find out how.