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That said, so ETSers, is an Altoids or a Sucrets tin more effective at protecting my garage door opener against the electromagnetic pulse from a nuclear blast?    
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After testing this out, mine survived the electromagnetic pulse, but the blast damaged the polished mirror surface. 
So now I will have to find another solution for a signal mirror in case this ever happens again in an emergency situation.  <img src="/images/graemlins/smile.gif" alt="" />