- Lid (cap)
- Corrugated top cut to the box footprint
- Poly liner
- Plastic bag liner inside the box
- Sold
- Often separately from the box
Lids
A lid (cap) is cut to the footprint of the box, so a 48 x 40 in lid goes on a 48 x 40 in box. It keeps dust and weather off the contents and gives a flat top for stacking when the load below is sound. A used lid is often cleaner than a used box, because it sat on the outside.
Ask for a lid when parts must stay clean in transit, when the boxes will be stacked, or when the contents could shift in a truck. Say so even if you are not sure. "Nice to have" is a useful answer, and the form has it.
Poly liners
A poly liner keeps resin, powder or food from touching the board. Resin and regrind shed dust and fibers into the board; liners keep the material clean and keep the board dry in a damp building. They also let you lift the contents out as a bag. For the plastics trade, a liner is routine, and we ask about it in every resin request.
A liner is not a barrier against everything. If the contents are regulated, the rules for the material decide the packaging. See the UN-rated page. If the contents are food, read food, hazmat and used gaylords.
Slip sheets are not lids
A slip sheet is a thin solid-fiber sheet laid under a partial-bottom box. It closes the base and keeps pallet nails off the load. It goes under, not on top. See slip sheets for sizes and use.
| Item | Goes | Does |
|---|---|---|
| Lid (cap) | On top | Covers and gives a stacking surface |
| Poly liner | Inside | Keeps the load off the board |
| Slip sheet | Underneath | Closes a partial flap bottom |
| Pallet | Underneath | Carries the box; solid pallets help partial bottoms |
Facts and figures
- Uline's 46 x 38 x 36 inch octagon bulk bin is 1,300 lb test triple wall, weighs 29 lb, is listed at 2,200 lb capacity and is recommended for resins, powders and produce. (uline.com, 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.)
- Stacking strength of corrugated often falls to about 50% of its potential when relative humidity climbs above 85% (AICC, November 5, 2025). (now.aiccbox.org, retrieved 2026-11-11.)
Terms
- lid (cap): A corrugated top cut to the box's footprint; often sold separately.
- poly liner: A plastic bag liner that keeps resin, powder or food from touching the board.
- regrind: Ground plastic scrap, one of the most common loads shipped in used gaylords.
- octabin: An eight-sided gaylord that resists bulging; also called an octagon bin or watermelon bin.
- sleeve: The four side walls of a gaylord made as one tube, set into a tray bottom.