If you want the cancellation to not be as bold, this works. It doesn't remove the impression and doesn't make the chip even look, uncanceled. It just removes the gold color.

Since I bought some chips like yours, and someone had already removed the cancellation most of the way, (without telling me, before they sold them on eBay!) I found some nice subject chips to experiment with. Already altered, I didn't think it hurt to finish the job.

I used a commercial brand that lists Glass cleaner and Label Remover on it. I think the chemicals that dissolve the gum from labels are the answer. By the way, it's not some volatile solvent (like acetone, which I wouldn't even try), just some very nice glass cleaner.

Look for something that says "Label Remover" on it, and find an old tooth brush.