Furnace & melting
Cullet
Recycled glass added to the batch — reduces energy use proportionally to its share. Internal cullet (own production) and external cullet (post-consumer) are distinct streams.
How Lean Glass works with this
In an audit or engagement.
This term appears across our hot-end audits, forming audits and Job Change Tool work. If you would like to discuss how it shows up in your plant, book a call — every engagement begins with an operational diagnostic, not a sales pitch.
Related terms
Read next.
Cullet ratio
Percentage of cullet in the total batch; higher ratios reduce energy use but require quality control on contamination.
External cullet
Post-consumer recycled glass cullet sourced from kerbside collection or industrial returns.
Internal cullet
Cullet from the plant's own rejected ware — higher quality and easier to manage than external cullet.
30-minute call with a senior practitioner.
Bring a problem — leave with a direction.