The salts will brush off, but they are normally an indication
of a damp wall, so they'll likely form again. Why was the wall
newly plastered? You probably have to stop the wall being damp,
or prevent the damp reaching the plaster.
the salts will continue to appear for a number of weeks. You could use a
dehumidifier until the plaster is completely dry. If you do paint the wall,
you must use a porous paint, which can be obtained from trade outlets and
sometimes even Homebase and the like. Do not use anything oil based (like
anti-condensation or mould paints) because it will only exacerbate the
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