In article , John Larkin
writes

Wet-slug tants are expensive (do they still have silver cases?) but
don't blow up like the dry ones. The dry slugs coat the sintered
tantalum (fuel) with MnO2 (oxidizer).
As I mentioned elsewhere some wet slug used conc nitric as the
electroyte (from memory 35 years ago) but very reliable.

--
ddwyer