If you have thick nails that need a little smoothing, or you don't like cutting your nails and prefer to file, then the emery boards will be a good choice. They're a great value because each file can be used multiple times, and there are 10 files per pack.
Gently slide the file surface over your nail in one direction, NOT in a back-and-forth, see-saw manner. Repeat until you have the desired shape and smoothness. Use the orange side to quickly reduce your nail length and the tan side to smooth and finish.
It's best to keep your files in a dry environment. Getting your files wet will cause the core to break down and the files to fall apart. To keep them free from excess nail dust, tap them off after use or give them a quick scrub with a dry nail brush.