I read a frugal report a while ago that discussed dryer lint filters. It said that the screens get build up on them from soap residue and fabric softeners and fabric softener sheets. They recommend washing out the filter once a month with hot soapy water. If you want to see how it gets clogged up before you rinse it out hold it under the faucet and see how little water flows through it. After do the same. I keep my filter really clean, you know family of eight=tons of laundry, but I was surprised!!