I buy small collections to repair/rebuild. Some come with boxes. I put them all on eBay and they always sell eventually, for prices ranging from $2 to $60. In five years of this, I only thrown away two or three boxes that would not sell for something more than my eBay and PayPal fees plus cost of shipping. The was a 2321 box with inset that recently was bid up to $550.
My basic rule is if it's Lionel (postwar era or prewar), someone will buy it. What I absolutely can't sell goes on the free table at a local TCA meet, and they are rarely not taken.