Velcro can get worn out and tired, just like any other item in the home. Velcro usually becomes worn out and has a hard time sticking due to dirt and other debris getting stuck inside, which in turn makes it impossible for the hook and loop sides to stick together. While Velcro can be replaced easily enough, there are simple and cost-effective ways to make your existing Velcro sticky again.
Lay the Velcro or article of clothing with Velcro on it on a flat surface.
Take the pet brush or other piece of Velcro and comb through both the hook and loop sides, allowing the dirt to lift. Place another piece of Velcro on top of the older one (hook on top of loop or vice versa), and press and release it several times. This will loosen the dirt and take the majority of it away.
Use a metal toothpick to pick through the rest of the Velcro. After using the pet brush or another piece of Velcro, most of the debris should be gone. The toothpick, however, will help you get the rest of the dirt out.
Spray the Velcro with antistatic spray to make it more difficult for dirt to collect in it.