[en] The use of prehistoric stone tools can be classified according to the usewear traces on the tool working edge. The polish resulting from the use of the tool contains minute amounts of the original worked material. Using the micro PIXE mapping technique, a comparative study of a set of experimental tools and a set of mesolithic end-scrapers was performed. For both sets of tools, increased concentrations of elements associated with the worked material were found in small localized regions. The composition of these regions was probed by point measurements and two main groups of P, Ca and S, K compounds were identified. The X-ray attenuation in the polish layer suggests that the deposited elements diffuse into the bulk flint