Hi Carlos
Thank you for your post. Unfortunately there is currently no visible method to detect which build types have been deleted. The only way to remove data from the warehouse is as follows:
Please be advised that this will affect all deleted data, and some history from the TFS system could be lost.
Also there is another post where some more information will be available:http://www.scrumforteamsystem.com/cs/forums/3472/ShowPost.aspx. They also have the same problem.
Regards.