This from our family dentist: "Have you ever seen a goat shaking its milk teeth? it is a mammal and it also has milk teeth. Who pulls them out? They shake and fall off by themselves. The same happens to human milk teeth. The milk-teeth roots dissolve gradually as the permanent teeth grow and eventually they fall off..."
Evidence: if you look at the milk-tooth after it comes off, you will notice that it has no roots!
More from the dentist: "These days I have notice that many of the milk-teeth roots are dissolving unevenly from one side, rather than from the bottom-upwards. As a result, the new teeth begin to grow side-by-side with the milk ones. I don't know why this is happening, but I suspect parents are shaking their children's teeth too early or too vigorously..."
Bottom-line? Just leave them alone. they will fall off painlessly. I remember shaking mine with the tongue till they came out...sometimes while in class!
Nothing is real unless it can be named; nothing has value unless it can be sold; money is worthless unless you spend it.