The best way to save presets for sharing is using all folder sinside Carrara instalation path. Take a look inside your Carrara instalation path and you will see 3 important main folders:

Presets - where almost all things are like shaders, textures, objects, backgounds, clouds, atmospheres and so on.

Scenes - where all scenes need to be saved

Data - where unfortunatelly you will find presets like the leaves

So if you use this folder structure you can very easy distribut your shaders that have link to image in textures folders, if the shader only have the shader file (procedural) you can out it anywhere BUT please use the folder structure.

Follow me at euQfiz Digital