That is bad. At least wash the board to take out as much of the gunk as possible before it spreads and does more damage.

Sometimes I swear, Apple must have had board meetings about how to have Macs Die in 10 years, with Bad Leaky Caps and Exploding batteries in their list.

BTW, this is not the only time I have heard of this, but iphone Li-Ion Batteries are exploding in people's pockets!!!

http://www.dailymail.co.uk/news/article-2972219/Man-suffers-degree-burns-iPhone-spontaneously-EXPLODES-pocket-yes-suing.html