On Thu, 18 Nov 2004 21:22:45 +0000, "Ed Sirett"
wrote:

hazardous in the wet weather. I beleive they are york-stone

IMHE, Jeyes Fluid and a stiff scrubbing brush makes a useful
difference. York stone is a reasonable surface on its own, it's algae
that causes the trouble. Pressure washing is great for a week, then
worse than ever (it encourages algal growth, as they love that nice
new porous surface).

--
Smert' spamionam