[Arran]

No they are not electrolytic capacitors, dry or wet, they are very large paper capacitors. When the model 76 and 86 were built electrolytic capacitors were not available so they used large paper capacitors of between 1 and 3 mfd and used extra filter chokes in the power supply to get rid of the AC ripple. In the case of Philco they used these in most sets built between 1928 and 30 and mounted them inside a tar filled can located somewhere on the chassis. They can be replaced by small electrolytics of course but the poly film substitutes are only about $2 a piece and they will last many decades without having to be replaced again.
Regards
Arran