Once upon a time I pulled out my old Xbox, but the controllers were full of battery acid and rust. This blocked electricity from passing through the terminals so they were unusable. I found that vinegar was a good way to fix the corrosion and will show you guys how to fix it.
Step 1: Set Up Work Area and Gather Supplies
You're going to need to open whatever electronic you are cleaning and remove any batteries in the sockets to avoid damaging the electronics. These flashlights should be alright, but if you are trying with something that has capacitors (a digital camera comes to mind) remember to power cycle it by holding the power button for 30 seconds. That should get rid of any leftover electricity.
You'll need some vinegar, cotton tip swabs, and a container to pour the vinegar into. Depending on the amount of rust or acid on your socket, you'll need varying amounts of vinegar.
Step 2: Cleaning Rust
Dip your cotton swab into the vinegar (not in your ears!) and gently rub the affected area. If it takes longer than 5 minutes to clean, go ahead and soak it in vinegar for a few minutes and then continue rubbing it. The vinegar's acidity will clean off the rust, but also any kind of coating on surrounding metal, so do not try this on gold or silver coated items. After a few minutes of work, your rusted battery socket should be as good as new!
Step 3: Cleaning Battery Acid
Battery acid shows up as a light blue or a white powder on your battery socket terminals. This, like rust, could prevent electricity's flow in the circuit. This is also a lot easier to clean than rust as there is a strong chemical reaction. Dip a new swab into vinegar and press against the corroded terminal. You should hear a fizz. This is due to the aforementioned chemical reaction taking place and is not related to electricity or your device malfunctioning. Gently rub the affected area and periodically press against it for the swab to soak up the battery acid.
Step 4: Clean Up
After you finish cleaning the battery socket terminals, it's time to clean up your workspace. If you have any vinegar spills, you can clean it up with a napkin, but don't forget to use soap and water after or else your desk might smell funny. After that, enjoy your spotless electronics!