Weird looking cylinders

[oceanlinerfanatic]

Anyone know whats up with these cylinders? They look quite strange.

[edisonplayer]

They look like they have a touch of mold edisonplayer.

[JohnM]

It’s not mold, it’s a chemical efflorescence caused by repeated/prolonged exposure to high-humidity.

[recordmaker]

The surface is most likely efflorescence as suggested but the patterns suggest some attempt play them with wrong reproducer or a recorder creating the patterns due to some sort of resonant effect