I had the opportunity to use the Noch Grassmaster the other day to repair a small section of scenery on the Nantucket Railroad display. The repaired spot is in the foreground.
Several well known modelers have never had any luck using the Grassmaster and have been very vocal about their problems. They all said they can't get the grass to stand up.
I like the tool, get excellent results and use it all the time. It's always in my traveling scenery bag along with several sizes and colors of the Noch flocking.
The trick seems to be to wet the area to be "grassed" with wet water, and then spray or drop on diluted matte medium (3 water to 1 matte medium). The Grassmaster likes a humid environment.
Hold the grassmaster about 2 inches above the ground and gently tap on the side. The "grass" will sprinkle out and stand straight up in the wet medium. After it area dries you can brush your hand over the grass without dislodging it.
I never work more than a foot from the grounding pin and always install a fresh 9VDC battery about every six months.
BTW - The structures shown in this scene are all made from resin wood shingle wall castings and shingle roof castings. I use the MicroMark casting products and it's all explained in my Easy Casting DVD.