They're so useful as general-pupose stirrers, daubers and smearers that I have a whole box of them (you can get them by the 100s, without the popcicle stains, at craft stores.)
A little thick for N scale usage, but I do recall slicing thin strips off of one to make bridge planks or something. Seems to me they may have had a waxy coating that had to be sanded off, but that may have been some other "found" material.
I keep an eye out for things like that, too. My latest rescue from the recycling bin was a box that nectarines came in (all the way from Spain!). Taking it apart, I salvaged several pieces of thin plywood that may prove useful someday, probably the day after I toss them during a cleaning spree.