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<p>[QUOTE=&quot;BadThad, post: 2427235, member: 17261&quot;]First off, the MSDS is now obsolete. The CFR has been updated by OSHA to HC 2012 which specifies the use of an SDS (Safety Data Sheet). Technically, as of June 2015, all chemical manufacturers must have an SDS for each of their products.</p><p><br /></p><p>The range shown on an MSDS can be ANYTHING a manufacturer wishes, there was no standard for the older HC1994. Typically ranges were used, i.e. 70-100%, but it was truly the &quot;wild west&quot; on what and how much was listed as they were not specified in the older standard (US). The HC2012 standard requires mfg&#039;s to show &quot;exact concentration&quot; unless it&#039;s considered a trade secret. Well, guess what? Almost all mfg&#039;s consider their compositions trade secrets so we&#039;re still seeing ranges used.</p><p><br /></p><p>The bottom line, you cannot fully trust the values shown on an MSDS and the same is true with an SDS. If you need an accurate assessment of concentration(s), you must have a COA (Certificate of Analysis).</p><p><br /></p><p>All acetone will contain traces of water unless it&#039;s certified as &quot;anhydrous&quot; or dried using molecular sieve. Acetone is hygroscopic and will absorb water (and other impurities) with exposure to air. I would not use the word &quot;adulterated&quot; as that implies something was intentionally ruined, a better word is &quot;contaminated&quot;, as this can be from the manufacture or by the end-user. With acetone, the impurities are usually volatile in themselves so, if the starting quality is ACS or better reagent grade, you really have no worries.</p><p><br /></p><p>As far as coins, a quality acetone from a hardware store is usually sufficient. Normally, these production runs are the same as they use for reagent grade. Typically, the only difference is in the testing and certification process although some chemicals may require additional steps such as filtration or tighter distillation. IMO, it&#039;s not enough to warrant concern for coin conservation.</p><p><br /></p><p>As far as rinsing with water AFTER using acetone, that&#039;s just plain dumb. Water just re-hydrates the surfaces inviting corrosion. If your coin requires a water rinse after acetone, then your acetone is contaminated or your coin surfaces still contain a residue (which can haze after being dehydrated with acetone). This is why I always recommend using the Polarity Ladder rather than just jumping directly to acetone.[/QUOTE]</p><p><br /></p>

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