In order to use heel liners, make sure that you’re using them with an appropriate shoe. Heel liners are often designed for specific types of shoes. This should be indicated in the product description. Follow the directions carefully. For best results, clean the inside of the shoe with a cloth before you insert the liners. Once the backing is removed, carefully position the liners against the inside of the heel and firmly press down. Replace your liners about every six months or more often if there are signs of wear and tear.