If the insoles in your Nike shoes have worn down or if you want to replace them with specialty insoles, you're in luck. The process is simple and inexpensive. Nike makes replacement soles for many of its shoes, and companies like Dr. Scholl's also make many types of insoles that can be used in Nike shoes.

Choose a replacement insole. Which insole you choose will depend on the reason for replacement and what kind of activities your Nike’s are made for. Choose an insole that is appropriate to your shoe needs. Insoles can be specifically designed for light activity like walking, or for greater impact sports like running or court sports. There are insoles for extra arch support and insoles to give extra support to the ball of your foot. Make sure that you purchase the correct size of insole, too.

Decide if you need to remove the current insole or simply line the new insole on top of the old one. It is not absolutely necessary to remove the original, especially if it is still in good shape and is glued into the shoe. Try placing the new insole on top of the old temporarily and try the shoe on; remove the original insole if the shoe feels too tight with both. Also pull out the old one if it is loose, falling apart or smelly, or if recommended by the manufacturer of the new insole. If the original is glued in and needs to be removed, pull back the toe end and carefully peel out the insole.

Use the original insole as a template to trace and trim the new insole if the new insole doesn’t quite fit or curls up a bit. Use a marker to trace and scissors to trim. Take off only the necessary amount, as you want a snug fit.

It is not necessary to glue the replacement insole in your Nike’s, but if desired, apply a thin, even coat of shoe glue or bicycle tube repair glue to the bottom of the insoles. Do not glue all the way to the edges. Leave about an inch of space. Put the insoles in place and smooth down with your hands while applying light pressure.

Your Nike's with new insoles may feel snug at first. Walk in them daily for a week to break them in. Contact the manufacturer of the insoles if they are still uncomfortable after a week.

Clean your insoles every so often by hand-washing them with warm water and soap.