There is stuff in the archive about removing the top cover, also details on resetting the metering rack if it is moved out of position. This often happens and is easy to put right.
The eyepiece is very easy to clean, but the 'dirt' visible on looking through the eyepiece (other than obvious dust) is probably not dirt at all, and is generally not dust trapped between the bottom of the prism and the focusing screen, it is 'desilvering' marks on the prism top. Unscrew the metal clip holding the prism in place and you may observe degraded foam padding has got under the protective plastic shield and attacked the paint and aluminium covering of the prism.
PS you may also find that the metering is tending to over-read. In this case the adjustable pots near the rewind will require attention.
