[Fontconfig] About removing a single font from a Gnu/Linux system

[Donn Ingle]

Hello,
I am posting from knode via Gmane, I hope this gets to the list.

I am the (slow) developer of Fonty Python and I am trying to get two things
done that, so far, I have not had any luck with. I hope someone on this
list can point me in the right direction.

Situation:
O/S - Kubuntu Dapper. 
Number of fonts (estimate) visible to fontconfig - 600.
When I want to use an app like Inkscape or Gimp, the number of fonts that
appear in the choosers is overwhelming. I want to learn how to cut them
down - how to "uninstall" or "remove" them without actually removing the
font files from the drive.

1. How can I remove a single font that is listed?
Let's pick on URWGothicL-Book - so that it does not appear in Inkscape or
Gimp.

2. How can I then, within ~/.fonts, install URWGothicL-Book again?
I chose it because it's a Type1 font. I am currently trying to include those
in Fonty Python. 
(I want a way that I can make link(s) to the font file(s) (pfg, afm, pfm)
within ~/.fonts such that the font is available in Inkscape (and other
choosers -- without the need for root login/su/sudo).
If there is another technique, bring it on. I gotta grok it before I can
Python it.

Aim:
I want to create a "font zapper" of some kind so that people who want to
manage their fonts can clear-up the chaos of system-wide fonts. I am
picturing a list of check-boxes and those that get ticked are visible to
fontconfig (listed in a font.cache-1 file, I guess) and those that are not
are *not* deleted, just sitting unnoticed by fontconfig.
This way, if a vital system font has been 'cleared' by mistake, the user can
pretty quickly re-tick it.

If anyone can help me out that would be great.

Donn.