I noticed from this picture and the 2 others you posted earlier,
that the shots were taken from the same opening or access.
Was this opening big enough to fit a hand into it with a toothbrush
and a foam spray cleaner (no-rinse) to clean the fins?

Any tips you can share in taking down the blower motor?

I have a 300D 1984 USA model to work on and I've been gathering
pointers from Brian Carlton from another forum of a similar subject.

I also want to replace the motor brushes if I can find a good source.
Any tips on this too?

I'll look forward to your answers.

Thanks.