Here is one for screws that won't stay tight in wood. For instance, screws in a hinge that won't stay tight, or a bunk bed ladder that the screws keep coming out of. If they are really small screws, take some saw dust and mix it with some wood glue to fill the hole. Then put the screw in before it dries. Larger screws, make some wood splinters using a razor knife to shave the corner of a piece of wood, about the size of toothpicks. Or, just use toothpicks, those work as well. I always seem to have some of these splinters lying around my workbench. Dip them in wood glue and then insert them into the worn out screwhole. Tap them in with a hammer, then cut or break off what is sticking out. The number you need to put in is determined by how big the hole is. You might need two or three for larger holes. Replace the hinge, or whatever the screw is holding, and let it dry. Should be good as new. If it doesn't hold, put in another toothpick/splinter.

