Unable to "Remove" firefox add-ons

[JD]

Hi All,
On Firefox 18.01

How can I Remove (not just disable - but totally remove)
these add-ons - as they do not provide the Remove option
like other well behaved add-ons. They simply came with
the installation (apt-get) of firefox, and very likely with
subsequent updates.

Global Menu Bar Integration
Ubuntu Firefox Modifications
Unity Desktop Integration
Unity Websites Integration

Thanx for your help.