Having furniture on carpets, rugs and floors will at some point leave an indent in your floors. For instance, under my computer chair I protect my floor with a chair mat.
Under other chairs I use a felt floor protector, it saves your floor and allows the chairs to be moved easily.
Eventually you'll have to replace your felt pad. After removing dirty pad, I clean bottom of chair leg with residue remover, like isopropyl alcohol. That way when I apply the new pad it will have a clean surface to adhere to.
