How is Recycled Paper Graded?
In North America those grades are defined in specifications published by the Recycled Materials Association (ReMA), formerly the Institute of Scrap Recycling Industries. Each paper grade carries a number — OCC is #11, DLK is #13, SOP is #37 — and a set of contamination limits for two different types of materials:
- Prohibitive materials: anything that makes the bale unusable as the grade, or that can damage mill equipment — plastic, metal, wax-coated board, foil, and the like.
- Outthrows: papers that don’t belong in the grade and make the bale less suitable for the mill using it — for example, boxboard in an OCC bale or brown grades in an office-paper bale.
This guide walks through the most traded grades, from the brown fiber grades to high-value office paper.
Brown Grades: OCC, DSOCC, and DLK
Corrugated is the highest-volume recovered fiber in North America, and it splits into three grades. They differ in how clean the material is and where it came from.
OCC #11 / Old Corrugated Containers This is used corrugated boxes with liners of test liner, jute, or kraft. Prohibitive materials are capped at 1%, and outthrows plus prohibitives at 5%. The grade allows up to 30% foreign (offshore) OCC, which typically has shorter fibers. Market reports often quote it as “98/2” or “95/5” to describe how clean a given supply runs.
OCC #12 / DSOCC This is corrugated sorted a second time, usually from supermarkets and industrial or commercial sites. It’s sorted to be free of boxboard, offshore corrugated, plastic, and wax, and it carries much tighter limits than #11. Mills pay a premium for it because it runs cleaner through the pulper.
DLK #13 / New Double-Lined Kraft Corrugated Cuttings. DLK is the clean trim and cuttings from box plants and corrugators, with liners of test liner or kraft. Treated medium or liners, insoluble adhesives, butt rolls, and slabbed or hogged medium are excluded. No prohibitive materials are permitted, and outthrows are capped at 2%. Because it’s pre-consumer and never touched by a shipper or shopper, DLK is the top of the brown-grade ladder.
Office Paper and High grades: SOP, SWL, HWS and CBS
These are the “pulp substitute” and deinking grades. Mills use them in place of virgin bleached pulp, so value depends on brightness and on keeping groundwood (newsprint-type fiber) and brown fiber out.
SOP #37 / Sorted Office Paper Paper typically generated by offices: mostly white and colored groundwood-free paper, free of unbleached fiber. It may include a small share of groundwood computer printout and fax paper. Prohibitive materials are capped at 1%, and outthrows plus prohibitives at 5%. Shredded office paper from secure destruction programs is commonly marketed into SOP when it’s kept free of cardboard and trash.
SWL #40 / Sorted White Ledger A cleaner, whiter step up from SOP: uncoated, printed or unprinted sheets, shavings, guillotined books, and cuttings of white groundwood-free ledger, bond, and writing papers. Colored paper is out. Total outthrows are held to about 2%, so a few manila folders or colored sheets can be enough to downgrade a bale to SOP.
HWS #30 / Hard White Shavings Unprinted shavings and sheets of white groundwood-free printing paper, typically trim from printers and converters. Because there’s no ink to remove, it trades as one of the highest-value paper grades.
CBS #43 / Coated Book Stock Coated groundwood-free paper, printed or unprinted, in sheets, shavings, guillotined books, and cuttings — think glossy catalogs, annual reports, and printer overruns. A reasonable percentage of fine-groundwood paper may be included. No prohibitive materials are permitted, and outthrows are capped at 2%.
Mixed and Residential grades: MP, SRP and SCN
In 2016 the industry retired the old numbered news grades (#6, #7, #8) and mixed grades (#1, #2, #3) and replaced them with three grades built around what MRFs typically produce:
MP #54 / Mixed Paper All paper and paperboard of various qualities, not limited by fiber type, sorted and processed at a recycling facility. It’s the catch-all grade for mixed office and commercial paper and for MRF output that isn’t sorted further. It typically trades at the low end of the fiber market.
SRP #56 / Sorted Residential Papers Sorted newspapers, junk mail, magazines, and printing and writing papers from residential programs, processed at a recycling facility. It should be free of containerboard and brown grades — OCC, kraft bags, boxboard, and kraft carrier board. This grade is the successor to the old residential news grades.
SCN #58 / Sorted Clean News Sorted newspapers from source-separated programs, converters, drop-off centers, and paper drives, with the normal share of rotogravure, colored, and coated sections. It must be free of excessive ink, brown grades, and non-paper material, and other papers may not exceed 10%.
If you see “ONP” on a price sheet, it usually refers to these news grades in their older form.
Quick Reference
Grade | ISRI # | What it is | Typical sources | Prohibitives / total outthrows |
|---|---|---|---|---|
HWS — Hard White Shavings | 30 | Unprinted white groundwood-free trim | Printers, converters | Very tight; confirm with buyer |
CBS — Coated Book Stock | 43 | Coated groundwood-free paper | Printers, catalog overruns | None / 2% |
SWL — Sorted White Ledger | 40 | White uncoated ledger, bond, writing paper | Offices, records destruction | About 2% total |
SOP — Sorted Office Paper | 37 | White and colored office paper, no brown fiber | Offices, shredding programs | 1% / 5% |
DLK — Double-Lined Kraft Cuttings | 13 | New corrugated trim | Box plants, corrugators | None / 2% |
DSOCC — Double-Sorted OCC | 12 | Re-sorted corrugated, no boxboard or wax | Supermarkets, DCs, industrial sites | Much tighter than #11 |
OCC — Old Corrugated Containers | 11 | Used corrugated boxes | Retail, grocery, distribution | 1% / 5% |
SCN — Sorted Clean News | 58 | Sorted newspapers | Source-separated programs, paper drives | Other papers ≤10% |
SRP — Sorted Residential Papers | 56 | News, mail, magazines, printing papers | Residential MRFs | No brown grades |
MP — Mixed Paper | 54 | All paper and paperboard | MRFs, mixed commercial | Broadest tolerances |
Contamination and Moisture
Most downgrades and claims trace back to one of three things.
Prohibitives. Plastic film, strapping, foam, metal, wax-coated boxes, foil-laminated paper, and food waste. In the high grades — DLK and CBS — none are permitted at all.
Outthrows. The right material in the wrong bale: boxboard in OCC, kraft bags in SOP, colored paper in SWL, groundwood in a pulp-substitute grade. Outthrows don’t damage equipment, but they lower yield and brightness, so mills deduct for them.
Moisture. Paper is sold by weight, and water is weight the mill doesn’t want to pay for. ReMA’s paper guidelines leave moisture terms to the purchase agreement, and buyers write them in — one 2026 mill RFQ for DLK and OCC set a 12% cap with deductions above it. Wet bales also mold, lose strength, and can be rejected outright.
Practical tips
- Separate at the source. Keep corrugated, office paper, and mixed paper in separate containers. One mixed bin turns three grades into the cheapest one.
- Break out your best fiber. If you run a box plant or print shop, keep trim and cuttings separate so they sell as DLK or HWS rather than OCC or mixed paper.
- Pull wax and poly-coated boxes. Produce and meat boxes are a common prohibitive in OCC loads.
- Store bales covered and off the ground. Rain and dock puddles are the fastest way to a moisture deduction.
- Keep shredded paper clean. Shred streams that stay free of cardboard and trash can be marketed as office grades instead of mixed paper.
- Agree on the spec in writing. Name the ISRI grade number, contamination limits, moisture terms, and how disputes are handled on every purchase or sales agreement.
