Cavemen used to get juice from fruits and other plants. They used the juice like paint, and just painted on the walls. Coloured rocks and minerals were also used, such a haematite and calcite. The paintings themselves were probably done using hands and fingers or sticks. Some of the most amazing finds of art in caves are the outlines of hands, where the artist held paint in their mouth, placed their hand on the wall of the cave and blew the paint over their hand leaving the outline of their hand on the wall. All this was done by the light of small lamps.