When we 
were in elementary school and had to write with big chubby pencils the diameter of your finger, we had Pink Pearl erasers. Making many writing mistakes that required much erasing, we reduced many a Pink Pearl eraser to eraser dust.If you did not have the right erasing technique, the Pink Pearl eraser would pick up the some of the pencil graphite onto the eraser itself. The next time you would need to erase an error, the Pink Pearl eraser would lay a huge black smudge over what you were trying to correct only compounding the mess. No wonder we took to the keyboard as soon as we could.
So as we were taking pictures of these snow white Iwako horse and hamster erasers, I began to wonder if the Iwako and Dream/Zensinsyoji Japanese erasers had the same bad erasing characteristics?
We will do a test and post the results shortly.