[Hallicrafters] S40 restoration

[Brent Seres]

Hi

I justa aquired an S40 which I am just beginning to restore. On opening 
it up, I noticed that some of the capacitors are of the usual wax and 
paper type. About half are black, shiny plastic type(.02, .05 mfd) . 
They appear newer than the others. Is this a recap job half done? Should 
I replace the black caps too?  The radio seems to work well, no hum, so 
I assume that after 60 years the filter cap must have been replaced.

Any advice for cleaning the corrosion off of the chassis?..Cleaning the 
front panel? Getting grime off the tuning capacitors?

I'm new to this. Recapped an S38, but that's about my only experience.

Thanks

Brent
VE3CUS