replacing arms and legs

I know there are other ways to do this, but this is how I replace doll arms and legs, if you can't just snap the limb back into the torso.
Whichever piece is the "male"--the part with the knob--gets stuck in the freezer for an hour or two.  Whichever piece is the "female"--with the hole--gets held over steaming water for a few minutes to enlarge it.  Be careful not to drop the item in the hot water!
Once the knob section is chilled--that is, it gets a little shrunken momentarily--I remove it from the freezer and at that point it is much easier to fit the two pieces together.  Of course, this only works if both the pieces are not broken otherwise.