Hello there, I'm experiencing something I didn't expect: the sides of my Ero's gold-plated steel nib's tines are slowly turning browner (it's really hard to catpure with a camera). It has begun, I don't know, maybe a month ago, by a very little stain, which is much bigger now than then. The surface remains perfectly smooth. Anybody knows what is happening? Thanks, Simon http://www.pixenli.com/images/mini/1387/1387523186074126900.jpgEnlarge http://www.pixenli.com/images/mini/1387/1387523200093632600.jpgEnlarge http://www.pixenli.com/images/mini/1387/1387523211095071600.jpgEnlarge http://www.pixenli.com/images/mini/1387/1387523111048285600.jpgEnlarge