[AMRadio] old round aluminum filter Capacitors

[John E. Coleman (ARS WA5BXO)]

What was in these things?  The inside of the can is lined with a perforated
brittle screen perhaps some carbon stuff. The center post is connected to a
foil which is wound in a spiral.  I don't think it is laminated foil?  The
other capacitor was the same except the foil same material as before was
laid in the can like an accordion. 

I don't get it.

I guess I have never actually examined these darn things before but I did
this time because I wanted to replace the insides of the cans with modern
electrolytic capacitors thereby hiding the modification.

Still learning
John, WA5BXO