To help with stone rorosin:Aside from the Rosenberg level conspiracy, is there any reason to believe that this rosin has a long shelf life? I've been using Nymann for around 30 years, but in the last decade or so have been disappointed by how quickly it turns to stone. I don't remember this being a problem in the '90s, and wonder if changes in formulation have affected longevity. Since I no longer play regularly, I would be happy to pay a premium for a cake which stays soft for two or three years.
Store
your rosin in Ziploc with a wet paper towel. (Poor man's humidor)
You know the little sponge inside some rosin containers? I used to think those were shock absorbers for when I dropped my rosin. But they serve as humidifiers. Keep them wet, and the humidity will keep your rosin sticky forever. try also cut sponges put in rosin containers for this purpose.
It keeps a long time this way.