Thanks ken about the 48 hour mist in water; but it ain't going to happen on this project;and for your information the RC Cleaner the other guy used did not remove the black soots... Pinheads .the limestone is bleached and blotchy ;and as hot water washing may ( I said may ) just bring residual salts and chems to the surface with the dry cycle; I am reluctant to proceed with taking on this guys contract until Im sure there are no salts . .do they make big litmus paper....or do I just stick my tongue on the side of the building.is enough to impress the client......Best Michael.... -- To terminate puerile preservation prattling among pals and the uncoffee-ed, or to change your settings, go to: <http://maelstrom.stjohns.edu/archives/bullamanka-pinheads.html>