B747-200 Air Atlanta Icelandic TF-ARO Athens 2004 Olympic Torch Relay 1:400**Discontinued**
We have seen this phenomenon before-dust was allowed to settle on the model over a long time & has left stains. The model looks like it is 'foxed' [ common on very old books !]. I don't believe this will come off. Humidity may have been a factor. I am actually curious how this stuff happens.