Not sure about the size, shape, and location of it but it obviously completes the circuit for a few things. Of course, copper is an excellent conductor and solders great, won't rust or corrode.
I would suggest getting a good soldering gun and carefully Re soldering the connections with rosin core solder. Clean it good if you haven't already withe no residue MAF cleaner.
A MAF code probably indicates a MAF problem of some sort!
Keith
