I've been asked about this a few times, so I thought I'd do a tutorial. This is a great way to easily remove glitter polish or designs that require many layers of polish and topcoat, or even just a plain mani. Also, this is a great method for removing soak-off gels, just soak your fingers for a longer amount of time (and you may want to use pure acetone instead of regular polish remover). The idea is basically to place the nail polish remover against your nail for a few minutes to break down the polish so that it is easier to remove. The foil (or plastic wrap) prevents the acetone from evaporating too quickly.
First, get your supplies ready. Use your favorite nail polish remover, preferably one that's nourishing/conditioning so it's not as drying as pure acetone. Make sure you have some cotton pads ready, too. I like to use Swisspers and cut them into quarters. I used to use some from Target, but they were much lower quality. I cut them in half and folded them b/c even though they were the same size, they were so full of air that one layer was not enough. Lastly, make sure you have five (or ten, depending on whether you want to reuse or not) small pieces of foil, squares that are about 2.5 inches on each side are sufficient.
Soak the piece of cotton with remover and place on the nail.
Take the piece of foil and wrap it around the finger and cotton, then fold the end over the finger.
Repeat this with the other fingers on the same hand. Best to do this one hand at a time, as it is not all that easy to work with foil-wrapped fingers!
Leave it on for three to five minutes, then, one nail at a time, remove the foil and use the cotton to swipe off the polish. Almost all the polish should be gone, but use the cotton to rub off little bits left behind.
This is the remains of my masquerade mani. I needed to scrub off the polish under the stones, but it was very easy overall. This was base coat, three coats of polish, three coats of glow-in-the-dark polish, and a thick layer of top coat.
Be sure to moisturize your nails and cuticles thoroughly afterward.
Hope this helps!