pkg db

[Baho Utot]

I rebuilt world using 11.0-p8 source and issued make package to build 
packages.  I put them into a repository and installed them. Now I would 
like to remove them from the pkg database so I can rebuild world using 
the old method as in the manual.  How can I remove the entries in the 
pkg database and not remove the installed packages?   I don't want to 
remove the installed packages and have a non-bootable system.

Thanks