NAFA sells cantor by the ounce. There are 3 grades - select, ordinary and shells. Some time they list them as 1s, 2s, 3s.
Selects (1s) are plump full castors that are dry to the touch but still flexible. Should not be dried rock hard.
Shells (3s) are empty castors, damaged castors and small ones that are dried rock hard.
Ordinary (2s) is everything else.
Castor is continually drying, unless stored in a freezer. Your castor may be dry when you shipmit, but NAFA will take a further reduction for shrinkage. Sometimes as much as 30%.
When you consider shrinkage and NAFA fees, there are usually better places to sell castor. Lure makers, state association sales and some country dealers. Check around before you ship next season.
Kind of the same deal as grading, 99% of trappers don't have a clue what real grading is. Castor is a hard product to work with, it continuously dries until it turns almost black and is worthless. NAFA handles it slightly different then FHA in that they have it in drying racks and you get what it is when they grade it out. FHA uses a straight forward deduction per shipment. Both methods work.
The buying customer does not want to buy 200lbs at a time that turns into 160lbs after drying.
I graded enough castor to know the stunts that some trappers pulloff like packing rocks or stuffing castor shells into castor pods to increase the weigh. Or ripping the castor out full of fat and membrane still attached or leaving the penis still half attached.
Not a lot of fun cleaning up moldy castor because it's was not dried properly.
Both auction houses have castor handling information on their web sites that explain the proper handling method for a reason.http://www.nafa.ca/wp-content/uploads/Beaver-Castor.pdfhttp://furharvesters.com/pdf/castor_eng.pdf
And as a matter of fact the auction houses set the price for castor that everyone else follows.