<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;"><DIV>Ben,</DIV>
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<DIV>An automotive catalytic converter comes to mind that occasionally could be "burned" out and purged by reverse flow in a "cleaning" operation, separate from the gas filtering. It may take a few to have replacements when the pressure differential gets large and you have neglected the required cleaning (burning, purging). Cleaning would seem to come from a diverting valve to the flare and an air supply (making flow backward). </DIV>
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<DIV>I have no idea how fine a CC will filter. Just a thought for comment, since you want inexpensive and readily available parts. </DIV>
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<DIV>One car dealer in Indianapolis had (I think I recall) about 60 of them taken off of new cars<U> in one night</U>. That's impressive... no matter how you look at it! Thieves like inventors, are very resourceful. </DIV>
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<DIV>Regards,</DIV>
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<DIV>Toby <SPAN><SPAN>Seiler</SPAN></SPAN></DIV>
<DIV>Seilertechco </DIV></td></tr></table><br>