list rpm repo gpg keys

[root@centos5 ~]# rpm -qa gpg-pubkey* --qf "%{version}-%{release} %{summary}n"
e8562897-459f07a4 gpg(CentOS-5 Key (CentOS 5 Official Signing Key) )
217521f6-45e8a532 gpg(Fedora EPEL )
6b8d79e6-3f49313d gpg(Dag Wieers (Dag Apt Repository v1.0) )

Now delete the repoforge gpg key (dag’s key).

[root@centos5 ~]# rpm -e gpg-pubkey-6b8d79e6-3f49313d --allmatches
[root@centos5 ~]# rpm -qa gpg-pubkey* --qf "%{version}-%{release} %{summary}n"
e8562897-459f07a4 gpg(CentOS-5 Key (CentOS 5 Official Signing Key) )
217521f6-45e8a532 gpg(Fedora EPEL )