I purchased this chip on eBay. Needless to say the seller did not mention that the cancellation stamp had been removed. In his defense, he may not have known it - I know I didn't until I just happened to see it in a bright light at just the right angle. I was a bit upset but felt it was just one of those lessons one learns in life.

You can see the missing cross hatching in the center of the chip where the "No Cash Value" stamp used to be. Of course the scan on eBay was not done at 300DPI so you couldn't see it.