On Fri, 15 Mar 2013 16:11:20 -0700 (PDT), RichA
wrote:

Everyone who has sent their camera in for service because of oil and
dirt is getting pretty much the same service report. RPL shutter and
CLN AA filter, along with some other cleaning and checks. Whether
this is an end to the problem, no one knows yet. Some seemed to think
the problem stemmed from an ill-fitting shutter mechanism where gaps
between it and the body allowed the dirt to get on the sensor.

So the issue is not related to the materials used in construction,
specifically the plastic frame?

:-)