Now to clean the old solder out of the main battery terminals. This is done to ensure you can put the new battery in easily.

Again, start carefully heating up the solder on and inside the main battery terminals. While the solder's hot and melted, use you Soldering Pump to extract the solder off of the terminal and out of the inside of the terminal. It might also be a good idea to have someone else use the soldering pump for you while you use the soldering iron.

If there's still some solder left inside the terminal, you may have to use something thin to file it out. Keep in mind that this is a last resort as there's a risk of tiny bits of solder going everywhere after filing.

After cleaning the terminals, the result should be something like the second image of this step.

Although it's a bit blurry, you can clearly see that the terminals are very clean and open.