If this is the original Pen, not the EE version, then be very careful cleaning the VF if it comes to that. The cover glass with the frosted half sits just a few thousands in front of the VF front lens. If there is dirt there then other than removing it from the plastic frame, (don't) the only way I've found to clean that very narrow gap is a business card cut to a strip about 1/2 inch. then wrap one layer of thin lens tissue around it and insert into gap. Drag out slowly. Repeat if needed. Use dry and if you can't get it spotless then get it as good as you can which will be good enough. If you take the cover off the VF bottom be VERY careful cleaning any surfaces. The VF contains both a full silvered front surface mirror and a semi-slivered beam splitter. If you wipe the aluminizing off the beam splitter you will render the bright frame either invisible or at least very very dim.
Just a heads up. Don't ask how I know all these things.