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<p>[QUOTE=&quot;Sunbird, post: 7600492, member: 116324&quot;]Hi all – I keep seeing claims that Q-Tips, cotton cloths, cloths in general, paper, and maybe loud music scratch coins.</p><p><br /></p><p>I&#039;m confused by these claims given the physics I thought I knew. I&#039;m no tribologist, but the scientific claim I&#039;m familiar with is that scratching requires that the scratching object be harder than the scratched object. Or possibly that it be at least of equal hardness.</p><p><br /></p><p>Is that purported scientific claim incorrect? If it&#039;s correct, then what are people talking about when they claim that a Q-Tip can scratch a metal object like a coin? How is that possible?</p><p><br /></p><p>Note that even if that claim is incorrect, it doesn&#039;t necessarily follow that a cotton swab can scratch a metal object. That would still need to be established. What&#039;s the mechanism, the physics, of a cotton swab, or cloth, scratching metal? What&#039;s happening down there in the weeds, so to speak, where the cotton fibers contact the metal?</p><p><br /></p><p>To be clear, y&#039;all aren&#039;t talking about foreign matter in the swabs and cloths right? Like sand or a tiny sliver of shrapnel your coin gear picked up in Iraq... The claims I&#039;ve read seem to be saying that a Q-Tip is literally scratching a metal coin, all by itself, no contamination, just the cotton fluffy fluff. I&#039;d like to nail this down to strictly cotton, fabric, paper as such, free of contamination.</p><p><br /></p><p>I&#039;m mostly thinking of gold and silver coins. They are indeed the softest of the coin metals, but even pure 9999 gold bullion is much harder than cotton or paper cellulose, so it&#039;s still a mystery to me how scratches would occur.</p><p><br /></p><p>I&#039;m also interested in your thoughts and experiences with paper in particular. Can clean paper scratch coins? Is there a certain type of paper that would definitely <i>not</i> scratch coins? (Maybe pure cotton or linen paper, like the primo Crane sheets?)</p><p><br /></p><p>I&#039;ve been thinking about using elegant paper envelope-like pouches or sleeves as packaging for individual coins, when shipped and so forth. Maybe brown kraft paper like grocery bags are made of. Not for long-term storage. And silver will tarnish without airtight storage of course, but even silver coins are normally shipped by dealers in crude plastic flips that are completely open on one end, so tarnish-proof packaging is not the norm anyway. I&#039;m concerned about scratches though. Anything graded or precious will already be in a slab, so this really only applies to standard bullion coins and bars, like your standard BU 2021 Silver Eagles, Maples, etc.</p><p><br /></p><p>Thanks.[/QUOTE]</p><p><br /></p>

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