Clearing Security Certificates on Firefox 3.6.X on the Mac OS 10
Recently I got the esteemed opportunity to spend a week working from a local hospital here in Colorado. The problem was that sometimes the self-signed certificate the network was using would need to be refreshed. Since the exception had already been added to Firefox it made getting a new copy of the certificate next to impossible. After messing around with it for awhile, I finally found out how to remove the old, stale certificate.
1. Got to Firefox > Preferences > Advanced
2. View Certificates
3. Click on Servers
4. In this case it was listed under (Unknown).