Felt boot liners cushion your feet and keep them warm, even in frigid temperatures. But after some wear, perspiration can cause them to smell and appear discolored. While machine washing and drying are not recommended for felt insoles, you can clean recycled felt liners easily by hand. For regular felt boot liners, you should spot clean them when necessary and air dry the insoles after wearing them.

Read the manufacturer's label or the product packaging before washing the liners. Many companies do not recommend machine washing regular felt liners. If you decide to machine wash, set the washing machine to the "delicate" cycle. Use a gentle laundry detergent and air dry the liners.

Place them in a cool location to air out. Spritz them lightly with a fabric deodorizer if stubborn smells remain.

Dampen a clean cloth with warm water. Rub any visible spots you see on your recycled boot liners.

Hand-wash recycled liners in a sink or basin filled with cool water using a mild detergent. Squeeze the liners a few times to coax debris from the soles.

Press the liners dry in a towel to blot away excess water. Place them on a flat surface to dry. Do not dry them near a heat source or in the open sun.