I sold my pampered Macbook AIR 2015 in the last month of the 1-y warranty. To my knowledge it never was in contact with water. After a month went by and a positive review for me, just got a return request for not working! Buyer opened himself the Macbook instead taking to Apple and sent photos. Do they look like a water spill or, rather to me, some caustic electrolyte with all the blooming? Is there a a potential source of such chemical spill in that corner ? How can show the pics to an expert at Apple?