Dopo una pausa di "lavori forzati" e stimolati da numerose discussioni ho proceduto al "wathering" (invecchiamento) some rolling stock.
The technique used is illustarta by Denny at the meeting of the Group N shivering Italy dedicated to modeling techniques and is well illustrated in this link:
http://fremoitalia.blogspot. com/2008/07/invecchiamento-rotabili-metodo-1.html
Here are the results of the tests
