or: Using A Simple Tool That You Already Have To Save Paint and Money.
You get to the end of a tube of paint, and you know there's some left, but you can't get it out. Wasting paint is never good, especially given the price of some oil paints. You consider, briefly, one of those devices that claims to "Get more paint out of a tube than you ever thought humanly possible!"
While considering these devices for squeezing more paint out of a tube, you wonder if there isn't a better way. There is, and it just involves a little common sense, a palette knife, and a hard, smooth surface. (There are other devices than a palette knife that would probably work, I just reccomend it because it is what the painter is most likely to have on hand.)
Use the paint tube normally, squeezing from the end, until it is 1/5 to 1/4 used. At this time, use the handle of the painting knife to squeeze as much paint out of the used area of the tube, preferably on a hard surface. Flip the tube over and repeat on the other side. The end of the tube will be flat, with almost no paint in it. Continue to use the tube, squeezing from the end, using the handle of the painting knife to force the last bits of paint out, as necessary. You will get quite a bit more paint out of the tube than normal, without buying some $15 piece of plastic.
Alternately, one can just use tin snips to cut the tube of paint open once the maximum amount of paint has been squeezed out by hand. However this results in nasty sharp edges, and often the paint in the end of the tube is dry.
Plus, carefully squeezing all the paint out of a tube is fun, mildly obsessive behavior. Yay!