Use nail polish remover: If the nails are stubborn, soak a cotton ball in nail polish remover and gently press it against the nail to loosen the adhesive. Apply nail strengthener: Once all press-ons are removed, consider applying a nail strengthener polish to maintain healthy nails and restore moisture. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.