Turbo Trainer Advice

"When it comes time to install a cell, you should be in the mindset that you never want to touch the cell with your bare hands or fingers. The oils on your skin and those in your fingerprints can be electrically conductive and act to slowly short the cell out if they bridge the insulation between the terminals of the cell, and some people who have more acidic skin oils can even cause corrosion directly on the cell itself (or even the movement if you touch it) as it sits inside the watch. Always use non-conductive tweezers, like those made from plastic or with wooden tips, to handle and move the cell around and if need be you can use the back end of the tweezers to help press the cell into place in a movement. If you find working with tweezers to be too cumbersome for changing cells and want to use your fingers, you can wear latex gloves or finger cots to keep from touching things directly."

https://blog.esslinger.com/watch-cell-storage-handling-procedures/