Sentence:  The stuff that was "really" valuable came from rare eraser colors. Teal or lime green, for example, were particularly hot in third grade. And orange <WSD>eraser dust</WSD>? Don't get me started. I would've traded gold bars for orange <WSD>eraser dust</WSD>. 
Meaning of the word marked with <WSD> tags:  The small curls of rubber that are left behind after using an eraser.