sand it off or just throw it out...everything in it is organic which is why it rots after 6months or so.
Do not tip it into drains. Not only may it clog them, it acts as a pollutant in storm water systems and streams.
Sheetrock is primarily gypsum, combined with sand and water.
Drywall mud is the thick, goopy white stuff you use to fill the seams between boards.
when you hang drywall, you have to tape off the seams with paper tape and "mud", then "float" the mud smooth. the drywall float is a flat metal tool on a handle that you drag across the mud to smooth it out, like when you smooth out the icing on a cake
Nothing
I use basic drywall primer over all of those.
lightly wipe the drywall mud after it drys
If it's small spread mesh tape over it, then mud it. If bigger than doorknob size, put a patch of drywall into it then mesh tape and mud.
When a large section of your ceiling's drywall is saggy, you need more than a spot repair. Sometimes the problem is so severe that removing an entire 4 X 8-foot drywall panel is the best solution. A few professional hints can make the job of drywall patch repair go more smoothly. Attic insulation should be cleared out Dispose of the old drywall Affix the nails with nail strips Drywall Panels Need to be Screwed In It's time to tape and mud
They install drywall, sometimes tape and mud it also, although commercially that is a more specialised job.
No, you plaster or mud it first.
Usually, there is drywall under the wallpaper. It is not difficult to remove the wallpaper (by steaming, or another method) to get to the basic drywall. Then, you can texture it and then paint it.
Yes it can if you stir it well.