What a used box keeps and loses
| Question | New | Used (Grade A) | Used (Grade B or C) |
|---|---|---|---|
| Stamp | Readable, full rating | Readable; rating applies if dry and square | May be creased or faded |
| Walls | Flat, full board | Close to new | Creased or taped |
| Bottom | Fresh flaps | Flaps intact | Check for crushing and punctures |
| Moisture | None | Dry | Check; damp drops the grade |
| Stack | To the rating | To the rating, with margin | Do not stack |
The factors that cost strength
- Humidity. Corrugated boxes lose approximately 50% of their compression strength when relative humidity rises from 50% to 90%.
- Time under load. Boxes stored under load in humid conditions may lose nearly 45% of their compression strength after 90 days.
- Cold and swings. Moving corrugated between temperature zones can cause condensation that weakens it.
- Overhang. A box that overhangs its pallet loses effective compression strength.
When used is the right choice
For a backup pack, used Grade A is usually the right call. It matches a new box on footprint and rating, and it is available sooner. For internal moves, returns and scrap, Grade B and C are fine. For export, ask for Grade A and dry. For food or regulated goods, used is not the choice. See food and hazmat.
A used box is also the more sensible answer when you are looking at what happens next. A box reused once more is a box not made. A box past reuse becomes OCC. See recycling.
Questions to ask a seller
Is it single trip?
Single trip, used once, is the top grade of used. Ask whether it was filled once, and with what.
Has it been wet?
Press the bottom corner. Soft means damp, and damp means a lower grade.
Can I see the stamp?
Yes. Ask for a photo of it, and compare it to the wall count in the listing.
Facts and figures
- Gaylord boxes range from 2 to 5 layers of cardboard, and many are sized for 40 x 48 or 45 x 45 inch pallets. (blog.containerexchanger.com, retrieved 2026-11-10.)
- US corrugated boxes had a recycling rate of 96.5 percent in 2018. (epa.gov, retrieved 2026-11-10.)
- Corrugated boxes lose approximately 50% of their compression strength when relative humidity rises from 50% to 90%, per industry guidance such as the Fibre Box Handbook. (paperindex.com, retrieved 2026-11-11.)
Terms
- single trip: Used once, the common description for top-grade used gaylords.
- ECT: Edge crush test, a rating of how much top load a board's edge carries; a stacking-strength number.
- OCC: Old corrugated containers, the recycling grade a box becomes when it can't be reused.