In electronics, desoldering is the removal of solder and components from a circuit board for troubleshooting, repair, replacement, and salvage. There are many techniques how to desolder. Check out videos How to Desolder Through-Hole Parts, Why Some Joints are Difficult and Desoldering Components – Tips and Tricks.
Heat guns, also called hot air guns
Heated soldering tweezers
Various picks and tweezers for tasks such as pulling at, holding, removing, and scraping components.
Vacuum and pressure pumps with specialized heater tips and nozzles
Rework stations, used to repair printed circuit board assemblies that fail factory test.
When searching cheap tools to do desoldering, I have found VACUUM DESOLDERING PUMP WITH HEATER – 30 W VTDESOL3 type combined soldering iron and hand operated pump to be a quite OK cheap product for desoldering task.
I have this type of product bought from Velleman years ago when it was yellow in color. I have found this type of combined soldering iron and desoldering to be best of the cheap desoldering tools for through hole boards desoldering. If you do just some desoldering every now and then, this works OK. If you constantly do lots of desoldering, get a good desoldering iron with a strong pump.
Here are some videos on using this type of desoldering tool: