TIPS Manganese steel is non-magnetic you should have a magnet with you when inspecting the machine during manufacturing. More Tips BLAST CLEANING MACHINES ABRASIVES Cast Steel Shot It is the most popular and efective abrasive for blast cleaning. The balls do brake with time to halfs, quoters and even smaller pieces (the fines are removed by seperator). With adding new shot it is achived a very efective mixture of round and angular particles.