Be thankful it isn't bags of fabric scraps from clothing that people decided to give and not launder. LOL! Yeah that went into the garbage (most of it).
If you have your stash in order by batiks, upholstery etc. within sight so everyone can see then you can kind of show them a list. You can separate the flannels just like in the stores. You could put like a little shopping list of what you need and mention sales. Go ahead and let them look or your wife so she can make her own list. You could tell them to send you a link of a really great website or pattern.