[Amps] How to safely clean an amplifier?

[Jack/W6NF]

I have just acquired a BTI LK-2000 amp that is in need of cleaning. It
appears that a majority of the junk inside is loose and can be removed
with a small vacuum. I would like suggestions for a suitable cleaner to
safely remove any deposits of dirt/crud that require more aggressive
cleaning. Any help would be appreciated.

Also, I have been to the BAMA site to download a manual for this amp but
the file comes up with a ".djvu" extension. None of the readers on my
computer will open this file. Does anyone know how that file might be
read? Alternatively, is there another site that has an LK-2000 manual
available for free download?

73,

Jack, W6NF