Sorry to see this marcelo,
Appears to be the LE Island Sands too.
Aside from ink what have you used to clean the pen, and also how what it stored? (appears from exterior issue not interior)
It's metal with some sort of very tough enamel-like, perhaps anodized finish, not plastics, but still some products could harm the finishes.
Hopefully someone will have suggestions to restore without recoating the surface.
A gentleman here, "Force" has renovated several Carene and may be of help.
GP, I know yours are widely traveled, have you seen anything like this on exterior? Lagoon & Sand are LE's about the same time as yours.
Edited by pen2paper, 18 March 2016 - 15:46.