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    <p>Thanks to all who replied to my post.  Very useful.</p>
    <p>Mario</p>
    <p><br>
    </p>
    <div class="moz-cite-prefix">On 2025-11-17 7:18 p.m., Martin,
      Michael wrote:<br>
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cite="mid:BN9PR03MB6170777697746E390CA48B78F2D6A@BN9PR03MB6170.namprd03.prod.outlook.com">
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                Non-UBC Email]</font></td>
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        Yeah, don't buy it.  Just make it as needed and keep a close eye
        on the students.  These days we only really use it to clean
        stubborn debris on masks and a few other relatively small volume
        applications. That said, we do have an acid waste
        neutralization system. </div>
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        -Michael </div>
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          <b>From:</b> labnetwork <a class="moz-txt-link-rfc2396E" href="mailto:labnetwork-bounces@mtl.mit.edu"><labnetwork-bounces@mtl.mit.edu></a>
          on behalf of Prashant Srinivasan <a class="moz-txt-link-rfc2396E" href="mailto:prashant@ucsb.edu"><prashant@ucsb.edu></a><br>
          <b>Sent:</b> Monday, November 17, 2025 8:39 PM<br>
          <b>To:</b> Beaudoin, Mario <a class="moz-txt-link-rfc2396E" href="mailto:beaudoin@physics.ubc.ca"><beaudoin@physics.ubc.ca></a>;
          <a class="moz-txt-link-abbreviated" href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a> <a class="moz-txt-link-rfc2396E" href="mailto:labnetwork@mtl.mit.edu"><labnetwork@mtl.mit.edu></a><br>
          <b>Subject:</b> Re: [labnetwork] Nanostrip/Purestrip bottle
          leakage: what do most labs do?</div>
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        <span style="font-size: 10pt; color: black;"><b>CAUTION:</b> This
          email originated from outside of our organization. Do not
          click links, open attachments, or respond unless you recognize
          the sender's email address and know the contents are safe.</span></p>
      <p style="margin-top: 1em; margin-bottom: 1em;">Mario,</p>
      <p style="margin-top: 1em; margin-bottom: 1em;">Is there a
        particular reason you absolutely need Piranha? I made the switch
        to RCA in our teaching cleanroom after getting tired of cleaning
        up spills. Even a few drops burn leave burn marks. RCA is fairly
        dilute (5:1/6:1) and the use temperature is only 70 C. Also,
        adding peroxide isn't as fraught. No matter how "well trained"
        the students are, the Piranha preparation process is
        unforgiving. Hazards to users, chemical waste and disposal risk
        (I don't have neutralization capabilities) drove my decision
        making.</p>
      <p class="elementToProof"
        style="margin-top: 1em; margin-bottom: 1em;">Prashant</p>
      <p class="elementToProof"
        style="margin-top: 1em; margin-bottom: 1em;"><span
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        </span></p>
      <div>On 11/17/2025 10:48 AM, Beaudoin, Mario wrote:</div>
      <blockquote>
        <p style="margin-top: 1em; margin-bottom: 1em;">Dear Labnetwork,</p>
        <p style="margin-top: 1em; margin-bottom: 1em;">As many labs do,
          because of safety concerns for the students, I banned the use
          the real pirahna etch in favor of Purestrip (Transene version
          of nanostrip).  The problem I have is that the solution
          eventually leaks from the bottle.  I have heard of others
          mentioning this also. </p>
        <p style="margin-top: 1em; margin-bottom: 1em;">I am now
          thinking of revising this policy and going back to old
          pirahna, despite the issues with safety and aging H2O2.</p>
        <p style="margin-top: 1em; margin-bottom: 1em;">Anyone have
          comments?</p>
        <p style="margin-top: 1em; margin-bottom: 1em;">Mario</p>
        <div>--<br>
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            src="cid:part1.W0SKrmiO.2CQzuIhY@physics.ubc.ca" class=""></div>
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      </blockquote>
      <pre><div>-- 
Prashant Srinivasan, 
Teaching Cleanroom Engineer
Electrical & Computer Engineering
University of California, Santa Barbara
Santa Barbara, California 93106
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