The same four percent, two very different bills
Take the defaults: 42,000 lb, a clean price of 42 cents and a downgrade price of 24 cents, with 4.5 percent reject measured against a 2 percent tolerance. Clean, the load is worth 17,640 dollars.
If the buyer deducts the reject weight and pays the clean price on the rest, you get paid on 40,110 lb and the contamination costs 793.80 — almost exactly what the rubbish weighs, priced at what the good material was worth. That is the intuitive answer and it is the one everybody assumes.
If the buyer reprices the whole load instead, all 42,000 lb settles at 24 cents and the load pays 10,080. The same 4.5 percent has now cost 7,560 dollars, which is nine and a half times as much. Nothing about the material changed. What changed was a line in the buyer policy that was never on the quote sheet.
Where the two rules cross over
The page prints one number that settles the argument: the reject share at which the two treatments cost the same. It is one minus the price ratio, so with 24 against 42 cents it is 42.9 percent. Below that share the whole load downgrade is the harsher rule, above it the weight deduction is.
Practically, no load anybody argues about is anywhere near 42.9 percent reject. That means a whole load downgrade is essentially always the expensive treatment, and it gets worse the cleaner the load is. A load at half a percent contamination repriced down a grade is being charged as though it were 43 percent rubbish.
Partial picking is worth nothing, or everything
This is the part that reads wrong until you see the arithmetic. Under a whole load downgrade, the money is not spread across the reject material — it sits entirely on one side of a threshold. Six hours of picking that takes 4.5 percent down to 1.35 percent crosses the 2 percent line and is worth 7,560 dollars, or 1,260 an hour. The same six hours removing half instead of seventy percent lands at 2.25 percent, does not cross, and is worth exactly nothing while still costing 168 dollars in labour.
So the useful question is never how much can be removed. It is whether what can be removed clears the line. If it does not, the hours are better spent stopping the contamination arriving, and if it does, almost no amount of picking labour is too expensive.
What has to come from the buyer
Three things, and none of them are knowable here: where the tolerance sits, which grade a load above it gets called, and which of the four treatments applies. They are policy, they differ between yards in the same town, and they are the difference between a 794 dollar problem and a 7,560 dollar one. Asking before the truck is loaded costs nothing.
The reject percentage is yours, and it is the number the whole page is most sensitive to. Sampling is a real procedure with real error, and looking at a load reads low almost every time, because what costs you is buried rather than sitting on top.
Questions people ask
How much does contamination in a scrap load actually cost?
It depends entirely on how the buyer treats it rather than on how much of it there is. On the defaults, 4.5 percent reject on a 42,000 lb load costs 793.80 if the weight is deducted and 7,560 if the whole load is repriced a grade down. Same load, same percentage, nine and a half times the cost. That is why the treatment is the first thing to establish.
At what point does a whole load downgrade become the fairer rule?
At one minus the ratio of the two prices. With 24 cents against 42, that is 42.9 percent reject. Below it, repricing the load costs you more than deducting the weight would; above it, less. Since almost no load in dispute is anywhere near 43 percent rubbish, a whole load downgrade is in practice always the expensive treatment.
Is it worth sorting a contaminated load by hand?
Only if the sorting gets you under the buyer tolerance. Under a threshold rule there is no partial credit: taking 4.5 percent to 2.25 percent when the line is at 2 percent removes real material and earns nothing. Taking it to 1.35 percent earns the entire downgrade back. The page works out which side you land on before you spend the hours.
How do I measure the reject share in a load?
Take a sample you can defend, sort it, and weigh both parts. Everything else is an estimate, and estimates made by looking at a load run low, because the material that causes the downgrade is usually inside it rather than on the surface. Measuring at the point the material comes in is more useful than measuring on the way out, since that is also where it can still be fixed.
What if the buyer sends the load back?
Then the cost keeps running after the truck leaves. The return trip is one figure, and the load still exists, still needs sorting and still has to be presented again. Treat the number the page gives for a rejected load as an opening balance rather than a total, and note that it is the only one of the four treatments where the material has not been sold at the end of it.