Poor
Those that can only eat a part of a shellfish are probably a bit poor.
Poor people can't even afford a whole shellfish. They have to settle with just a part.
びん, ひん
まず
None
And since they are poor, they are getting these shellfish parts from the trash bin (びん). It's quite unfortunate.
Imagine a poor person going through a garbage bin to find only a part of of a shellfish. What a sad sight.