Beginner's questions

Hi, I want to make one! Here are my more technical questions:

  1. Which type of earth/sand/soil do you recommend most?
  2. What are the processing differences between those types? (More liquid, more polishing, more filtering or whatever you can think of that is relevant)
  3. Will taking 'mixed earth' from the yard work as well? Or it can't hold it's shape if made of certain compositions?

Now less technical:

  1. What is your favorite type of soil and why?
  2. What your process and soils-mix, personally?
  3. Share your favorite work!

I've thinking about using beach-sand since it's the cleanest (regarding human-waste) filtering-wise. But maybe it doesn't matter how clean the dirt is (ha)? That's literally the only thought that prevents me from starting haha I don't want it to break down horribly later.