You could try caustic soda, Dave. Although you will have to make sure
you rinse every last crystaline trace of it off the walls when you're
done unless you want to have visitors telling you how their clothes
have developed holes after leaning on your friend's panelling (this
will often occur after clothes have gone through the wash).
See he
http://www.motherearthnews.com/libra...tain_Chemistry

There are also strong pastes that seem to do a better job of stripping
old paint, especially on uneven surfaces.

And one last thing - a tad dangerous - but I've always found a good way
of creating cheap razor-sharp scrapers is to cut convex pieces of scrap
glass with a glass cutter. When the edge wears off, cut a new piece.
Get your glass from a glazier's skip.