While in the process of doing this stuff, remember what you are looking for. In this case, a small spring. Just thik small. There is doll house stuff you can use.(Newspapers, books, lunch boxes, pets) Black sandpaper looks like black top. Use real sand and small stones for boulders. Pick through the trash and look at the shapes. Heat a nail or pin for "metal punctures"
Be outrageous, it's free