[CentOS] Dug myself into a hole

I just build a CentOS 6 machine to replace my old machine which
broke to where I could not fix it.  In attempting to get the applications
running which had worked on the old machine, I did updates from several
repos such as rpmforge, atrpms, livna, epel,  etc.
Some of the attempts ended going down blind alleys.

Now I have a mix of rpm's from various sites that I do not need, but they
are listed as dependencies of other rpm's.  

The rpmforge rpm's are marked with "rf".
Is there a process to check which of these rpm's are also in the
base libraries and force them back in?

I really do not want to go back to square 1 and reload the system
from scratch.

Bob S