Laser Selectivity on Cleaning Museologic Iron Artefacts

three distinct techniques were used to clean fe alloys objects with surface corrosion. these objects are presently kept in physics museum of the university of coimbra. the techniques used were mechanical, chemical (edta solution) and laser (pulsed co2 and nd:yag - q-switch). the chemical characterisation and the evaluation of the cleaning degree were done by transmission 57fe m？ssbauer spectroscopy. the results suggest that: the mechanical process of cleaning does not allow total removal of corrosion, reaching easily the substrate and so causing mechanical damage; the cleaning method using edta in confined environment and high controlled conditions, removes the corrosion products efficiently, without damaging the surface; and the cleaning methods using laser although not achieving complete removal of corrosion, show clear characteristics of selectivity when acting on the corrosion layer or on the metal surface.