Our intake log has a free-text field called prior contents. The entries are short — Corn syrup 42 DE, original label intact, or Unknown, label removed, heavy amber staining — and they are the most consequential eleven or so words anybody at this yard writes.
Everything downstream keys off that line. Grade ceiling, permitted use, wash cycle, price, and whether the container is even allowed onto the intake bay.
Why history beats condition
Because polyethylene is not an inert barrier. It is a semi-crystalline polymer with amorphous regions that absorb organic compounds during service — surfactants, glycols, solvents, plasticisers, many agricultural actives. The absorbed material sits in the wall, and when you empty and wash the container, the surface is clean but the wall is not.
It then desorbs slowly back out, over months, into whatever you put in next. That is why a container can pass a visual inspection, a smell test and a swab, and still contaminate a product two fills later.
You cannot test your way out of this at any sensible cost. So the industry — the honest part of it — uses provenance as a proxy, and provenance is a record or it is nothing.
What the record actually controls
| Record | Grade ceiling | Food use | Wash cycle | Typical price effect |
|---|---|---|---|---|
| Documented edible, benign | Food grade | Yes | Hot caustic + sanitise | +$90 to +$140 |
| Documented industrial, benign | Grade A | No | Per residue class | baseline |
| Documented industrial, surfactant | Grade B | No | Extended rinse + defoam | −$25 |
| Documented agricultural chemical | Grade C | Never | Triple rinse, dedicated | −$60 |
| Unknown, label absent | Grade C | Never | Triple rinse | −$70 to −$90 |
| Outside permitted list | Refused | — | — | Not accepted |
The spread between the top and bottom rows is well over $200 on an object that may be physically identical in both cases. That is not arbitrary pricing. It is the market pricing information, which is exactly what it should do.
How to keep your record intact
If you generate empties, four habits are worth up to $40 a container and they cost nothing:
- Leave the original product label on. This is the single highest-value thing you can do. A legible label is a provenance document.
- If the label has to come off for internal reasons, write the product name on the cage in paint marker before it does.
- Do not repurpose containers internally without recording it. A tote that held syrup and then held wash water is now a wash-water tote, and if nobody wrote that down, it is an unknown.
- Keep them under cover. Weather destroys labels faster than anything else, and a rain-damaged label turns a food-grade container into a Grade C one.
What we refuse, and why we say so
Containers whose declared residue falls outside our permitted list do not come off the truck: pesticides and biocides, oxidisers and peroxides, aromatic and chlorinated solvents, pharmaceutical actives, anything requiring specialist rinsate treatment.
We decline them at the gate rather than accepting and subcontracting, which is the industry's usual manoeuvre. Then we tell the seller which kind of processor they actually need, at no charge, because a referral costs us nothing and a mishandled residue costs everybody.
The uncomfortable implication for buyers
If a seller cannot tell you in writing what a container previously held, you are buying an unknown and it should be priced as one. Not as a bargain, not as a clean tote with missing paperwork — as Grade C, non-food, non-potable, static duty only.
That is a slightly awkward thing to publish, because it applies to us on any day we lose a label. It applies to us anyway. The rule is only worth anything if it survives contact with your own inventory.