Measure it - Establish global & local metrics that link process owners and operators to the total cost structure. Begin the basic scorecard for material waste.
Map it - By application of various lean tools, come to understand the causes of the material waste. Most tools such as value stream mapping focus on labor and lead time, similar tools can help map out and put material waste in a spot light.
Fix it - Use the scorecard to drive frequent corrective actions. Follow Lean, DMAIC, PDCA, Toyota Kata principles to improve on that waste.