Real Dirt and Magnetic Particles

[nachoman]

Keep in mind, most fungi and bad stuff don't require much to spread, but takes moisture in order to grow. Keep your layout room dry, and problems will be less likely. I've had mold grow on white glue and newsprint before, if it stays moist. I also had some moths raise in some lichen/natural weeds I used for trees, and the natural trees on my brother's club layout attracted a herd of mice grazers. I bake the dirt I collect from my yard, though. I think about 350-400 for an hour or so.