The short answer
Before you buy surplus resin, get the exact producer grade, the lot numbers, the original COA, the date of manufacture and the storage history, with photos of the labels and packaging. Test a sample from the actual lot for moisture, melt flow, color and contamination, and trial it in your part. Expect as-is, all-sales-final terms, FOB the seller's warehouse, and check that you can get any FDA or UL paperwork your part needs.
Good surplus can be a real saving. It can also be a gaylord of something nobody can identify. The difference is almost always in the paperwork and the storage history, and you can check both before you pay.
Prime surplus vs. off-grade vs. regrind
Prime surplus is first-quality resin left over from a canceled program, a part change or an overbuy. It sits in the producer's original packaging with the original labels and lot COA. Our current surplus lot is an example: a glass-filled polyester bought for an automotive program that was canceled. Off-grade and wide-spec resin was outside the producer's specification when it was made. Regrind is ground scrap with a heat history. All three get called "surplus" by some sellers, so ask which one it is. The tiers are explained in prime vs. off-grade vs. regrind.
Questions to ask the seller
| Question | Why it matters | Red-flag answer |
|---|---|---|
| What is the exact producer grade and color? | Family names ("PBT 30% glass") cover dozens of grades that mold differently | Generic description only, or "similar to" a grade |
| What are the lot numbers, and can I see the labels? | Ties the material to its COA and to the producer | Labels removed, gaylords re-boxed, or mixed lots in one box |
| Do you have the original COA for these lots? | Measured values for the lot as it was made | Only a data sheet, or a COA whose lot number does not match the label |
| When was it made? | Producer shelf-life statements count from manufacture | Unknown, or no date anywhere on the packaging |
| How has it been stored? | Indoor, sealed, temperature-controlled storage keeps it close to new | Outdoors, in a trailer, or "not sure" |
| What condition is the packaging in? Can I get photos? | Torn liners mean moisture and contamination | Refuses photos, or photos show open or patched liners |
| Is it prime, off-grade or regrind? In writing? | The price and the risk are very different | Will not put the description on the quote |
| Why is it surplus? | A canceled program or overbuy is a normal story | Vague, or the story changes |
| How much is there, and will you split it? | Many lots are all-or-none or sold by the truckload | Unclear quantity, or quantity grows when you ask |
| Where is it, and can the site load a truck? | Freight is on you, and a site without a dock costs more | No address until after payment |
| Can I get a sample from this lot? | The only way to test before an as-is sale | No sample and no inspection allowed |
| What are the terms? | As-is and all sales final are common for surplus | Pressure to pay fast, or unusual payment methods |
A starting checklist. A single red flag is not always a deal breaker, but get the answer in writing and test before you buy.
What to test on a sample
- Moisture as received, for nylon, PC, PET, PBT, TPU, ABS and acrylic. High moisture usually means a longer drying time, not a bad lot, but it tells you how the material was stored.
- Melt flow (MFI) on dried resin, at the same condition as the COA. It should land in or near the COA range.
- Color against a part or plaque from your current material.
- Contamination: spread a few pounds on a white tray and look for foreign pellets, fines, dust, fibers and dark specks.
- Density or ash if the filler level matters, for example to confirm 30% glass.
Age alone is not a reason to reject a lot. See do resin pellets expire? for what changes in storage and how to requalify old material.
Will it work in your part?
A surplus lot is whatever grade someone else needed. If it is the exact grade you run, a moisture check, an MFI check and a short run are usually enough. If it is a different grade, even in the same family, treat it as a material change: compare the data sheet, check shrinkage, run a trial in the production mold and get customer approval where the part requires it. Our guide to finding an equivalent resin grade covers what to match.
Terms and freight
Surplus is usually sold as is, with all sales final, because the seller is clearing inventory. Most lots are FOB the seller's warehouse: you arrange and pay for pickup, so the location affects your total cost. Ask whether the site has a dock and can load gaylords, and whether the quantity can be split. Be careful with any seller who pushes for fast payment by an unusual method or won't let you see the material; see resin supplier scams and how to avoid them.
Regulatory paperwork
- FDA food contact. The producer states compliance for a grade under specific 21 CFR sections and conditions of use. You will need the producer's current letter for that grade, and the lot number to show your material is that grade. The finished article is still the manufacturer's responsibility. See FDA food-contact resin.
- UL 94 and RTI. UL recognition (the yellow card) covers a specific grade from the recognized producer, in the colors named on the card. Surplus of the exact recognized grade, traceable by lot, is still that grade, but check that your UL follow-up program and your customer accept the source. A similar grade from another producer needs its own recognition.
- Automotive and medical. A new source of an approved material may need customer notice or approval even when the grade is identical.
How we can help
We list surplus lots that a polymer chemist has reviewed, with the COA available, and we tell you if a lot fits your part before you commit. If you have surplus to sell, send us the details. If you would rather buy a fresh lot of your exact grade, send the grade, quantity and ship-to city. We aim to send your quote within one to three business days.
Common questions
What is surplus resin?
Resin someone bought and no longer needs, usually because a program was canceled, a part changed or a buyer overbought. Prime surplus is first-quality material in the producer's original packaging, unlike off-grade or regrind, which are lower tiers.
Is surplus resin as good as new?
Prime surplus in sealed original packaging with a matching COA is the same product as a new lot, apart from its age and storage history. Check moisture, melt flow and color, and run a trial before production.
What paperwork should come with surplus resin?
The original lot COA, photos of the labels showing grade and lot number, the date of manufacture, and the data sheet. If your part needs FDA, UL or other compliance documents, ask the producer for a current letter for the grade.
Can I return surplus resin if it doesn't work?
Usually not. Surplus is commonly sold as is, all sales final, so test a sample from the actual lot before you buy.
Who pays freight on surplus resin?
Surplus is often sold FOB the seller's warehouse, and the buyer arranges and pays for pickup. Ask where the material is and whether the site can load a truck.
Can I use surplus resin on a UL-rated or FDA part?
Only if it is the exact listed or compliant grade, traceable to the producer by lot number, and your customer and quality system accept the source. A similar grade from a different producer needs its own listing or compliance statement and a qualification run.
Tell us the grade you need
A polymer chemist reviews every request, then matches your grade or finds a qualified equivalent and prices it.
What to send for an accurate quote
- The grade name, from any supplier, or a data sheet
- Color (natural, black or a custom match)
- Fill type and percentage, if any
- Melt flow, if you know it
- Quantity for this order and what you use in a year
- Ship-to city and state or province