The thought about it being sanded never crossed my mind until someone said that, and i realized it immediately. Im going to get a coin microscope today because i have numerous coins i have questions about, including a 2003 jefferson nickel where some of the letters on both sides appear to be doubled.
Doubling is usually easily visible by the naked eye. Once you get into microscopes ... well many of them add distortion and use algorythms that create things. Then you add on it people who want to "find" things and certain patterns start making ppl think they have something when they don't. you need to start learning about the minting process and what is and is *not* an error. many ppl think when they see "doubling" that it is a mint error when 99.9% of the time it's (a) Machine/Mechanical Doubling or (b) Die Deterioration Doubling. Learn about those first and you'll make sure you are not sorely disappointed time and time again. (a) https://www.ngccoin.com/news/article/5688/Double-Dies-vs-Machine-Doubling/ (b) Die Deterioration Doubling. the die is getting worn down and losing it's crisp, detailed edges, and shows a shelf like pattern of the letter next to (extension of) the letter itself. Versus true Doubled Die. see this ==> https://www.cointalk.com/threads/got-some-doubled-dies-on-these-nickels.325359/#post-3213433 Mint Error information https://en.wikipedia.org/wiki/Mint-made_errors https://en.wikipedia.org/wiki/US_Error_Coins
Given this is how rapidly coins are minted, find one under magnification that isn't doubled somewhere, and there's an achievement!