If it’s taking longer than usual for your clothes to dry or the clothes are super hot after a dry cycle, you could have a build-up of lint—even if it’s not visible in the lint screen. “Lint is an extremely flammable material,” says Jason Kapica, president of Dryer Vent Wizard. “Oxygen moves through a dryer and its vent when the machine is running. There is a heating element inside the dryer providing a potential ignition source.” Reduce the risk by removing the lint from the lint screen after each load and get a yearly cleaning of the dryer vent line. Also, make sure to never put any of these 14 items in your dryer.