I think the only way to do it would be to clear out the data in Manage Applications. There are no other options in there, the normal long press or Menu key doesn't give the facility.
First of all unpair any old connections you no longer want by long pressing and select unpair. The to clear the cache it Settings>Applications>Manage Applications, then if you are on Android 2.1 press Menu again, Filter>All - then scroll down to Bluetooth Share and then clear data. Then turn your phone off and reboot it and they should be gone.
Just tried it with a couple on my phone and they have gone, but the two that I left paired are still there.