Abstract: It is suggested to machine contaminated surfaces, in particular radioactively contaminated concrete surfaces and masonry with pneumatically actuated striking tools. It has been shown that this is an extremely low-dust machining method with which the essentially the particles are struck off in the size order of 0.2 to 2.0 mm. The method may be realized with a device (1) with which in a housing (2) several chambers are arranged over one another. Most preferred at the top a pressurized air feed chamber (10) is fed via a pressurized air connection (3). Therebelow there is located a pressurized air suction chamber (12) which comprises a suction connection (4). At the bottom there is arranged a collecting chamber in which chisel-like hammer bolts (51) are effective. The hammer bolts which are part of the striking tools (5) project out of the housing (2).