Selling wholesale and to dealers
Updated
Selling to somebody who will resell, which is a different negotiation from selling to a collector.
A different transaction
A collector buys one specimen because they want it. A dealer buys material because they can sell it, at a price that leaves them a margin.
Which means the conversation is about the lot, the average, and how fast it will move, rather than about the best piece in it.
What a dealer buys
Material they have a market for, which is narrower than you expect.
Quantity, because a table needs filling at several price points.
Documentation, which is what lets them resell at a better price than undocumented material.
And a clean legal history, particularly for anything self-collected: a dealer who resells material collected for noncommercial purposes has inherited your problem.
Lots and flats
Material moves by the flat, priced as a lot rather than piece by piece.
Which means the average matters more than the best piece, and padding a flat with poor material lowers the whole lot's price rather than adding to it.
Sort honestly into grades and price each grade. A dealer who finds the bottom third unsaleable will remember.
Keep the documentation with each piece even in a lot. A flat of labeled specimens is worth substantially more than the same flat unlabeled, and it is the cheapest value you can add.
The relationship
This trade runs on repeat dealing between a small number of people over decades.
A dealer who knows your material is described accurately will buy again without inspecting everything, which is worth more than any single transaction.
And the reverse: one lot with undisclosed damage or an optimistic locality ends the relationship and the story travels.