How to remove Header pins
Many off-the-shelf modules have header pins that can be difficult to work with, whether they are facing the right way or are the wrong configuration (vertical instead of horizontal, vice versa.) - Sometimes it can be easier for you to use wires instead of header pins, and you need a way to remove the existing header pins without causing damage to the module or causing a mess with a pair of side-cutters.
Removing the header pins is actually a very easy process when you remember that metal doesn't stick to plastic too well:
Step by Step instruction
you'll find the pins have left old solder there, plus whatever manufacturing chemicals they've used, and can generally look pretty messy, We can clean it up easily though: