burnt deans?

[ReV:-O]

hi guys,

ive got the MMM combo and 6s lipo with deans all round. when I connect the lipos, there is usually a huge spark (though not every time). I have noticed on the ends of my deans plugs it is no longer gold, but turned sort of silver. everything is pretty much brand new with only about 4 runs on it. are my deans wearing out already?

thanks