Follow the physical flow
Separate collected material, usable recovered output and the input actually needed by a process. Losses and rejected material belong in the balance.
WORLD MATERIALS CENTER
Secondary materials
Separate collection, recovery, quality and verified recycled-content claims.
MATERIAL CONTEXT
Secondary materials
Separate collection, recovery, quality and verified recycled-content claims.
Keep quality visible
Composition, contamination, variability and supplier acceptance criteria affect whether a secondary material can be used.
Distinguish estimates from claims
A physical balance is a planning calculation. Verified product content requires the appropriate chain of custody, accounting method and supporting records.
TAKE IT FURTHER
Turn the context into a brief.
Educational starting points, not grade selection or qualification.