What do auction firms do with consigned collections that have both great coins and junk?

SanctionII

Say the consignor has a large collection that includes several pieces that will bring large bids and several other pieces that are widget items (junk silver, circulated wheaties from the 40's and 50s') and is willing to consign to the auction company only if it will take the entire collection.

What will the auction company do with the widgets it has to take to get the good stuff?

Bear

They take the widgets and either bunch them into group lots

and or list the items in a section of the auction called economy coins.