Interesting discovery

I found this interesting today. I was having a hard time connecting my Better Cables speaker cable with spades to my Dynaudios because they are stiff and the spades are too large. I decided to cut off the spade and expose the bare wire. I found a white powder around the soldered spade connector and terminal end of the speaker wire. One soldered connection was slightly loose, as though the solder had cracked. Also, the wire was solid copper, twisted with two pair (no wonder it is so stiff). Anyway, is that powder oxidation or the solder breaking down? I don't know if the sound is better, but the wire connection to the speaker is finally very secure. It makes me wonder what I spent my money on. Any thoughts?