SL;
Going back to your post No.7, Aluminum wiring in domestic (residential) or any electrical systems for that matter, particularly when in contact with dissimilar copper is known to be a problem in waiting...and unless you're in the Mohave desert, where rate of corrosion is quite reduced due to the RH seldom being over 3% (we know you're in PA), Galvanic corrosion IS occurring at some rate, so it wouldn't be a bad thing for you to inspect your load center for Alu wiring and if found, proceed with some preventative maintenance (at all ends of it, not just within load center) BEFORE problems arise!
Recommended Reading:
http://inspectapedia.com/aluminum/Al..._Reduction.php
Cheers from Connecticut!