Removing paint from soft stone ??????????

["tlp, the languedoc page" <tlp@zzzzzzzz>]

Hi

Introducing myself :

I'm Peter from Languedoc, France and am renovating an old medieval stone
building

I hope that one of your members can help me with my problem.

I have some problems with a stone staircase.

I've uncovered centuries of paint & plaster to get back to the old stone,
which I will renovate and keep as "pierre apparent". My problem is that the
stairs themselves have been painted. Not once, but many times in various
colours. It appears to be oil based paints applied directly to the stone.

The staircase is circular with a hollow centre section. Individual steps are
carved to produce a central spiral (i.e. you can see the roof on the 4th
floor from the basement by  looking up the centre of the staircase).

Do you have any ideas how I can remove this paint without damaging the
original stone ?

Regards

Peter

History
The property is built over medieval arches dating from around 1100 in
a Languedoc town market square. From the evidence uncovered, the rear
section could be older than this. Many of the original buildings were
destroyed in a siege around 1200, and subsequently rebuilt on the
arches which survived. The building was probably used for leather
working at this time.
The staircase has been dated as around 1350. It is on 4 floors. I
have some photos here :
http://tlp.netfirms.com/stairs1.jpg
http://tlp.netfirms.com/stairs2.jpg
http://tlp.netfirms.com/som4orig.jpg
http://tlp.netfirms.com/som5orig.jpg
http://tlp.netfirms.com/som9orig.jpg