Ask the same question of everything.

At every step of making, ask why each material is there, and whether a waste could take its place. Each waste becomes the input to the next process. The loops branch and keep generating new questions.

The five steps, arranged as a cycle: make something; list every material in it; ask why each material is there; ask whether a waste could replace it; use the waste from one step as the input to the next. Solving one problem creates the next question. A new waste appears. The loop repeats.

Repeat continuously. Iterate, improve, reduce impact.