Description: The detail of incrustng solids on the surface of the stone tools. Petrified, originally organic substance covers the tools all over the places where it clung in form of gooey pulp created during the proces of tanning. The gooey substance scraped off the wrong side of the worked fur not only stained the hands of the prehistoric tanners but also the surface of the tools used during their last work shift. Nowadays, we can find them in form of sediment loads of petrified, light grey incrustations covering some parts of the stone inventory used in the process of tannig.