On my 2009 4Runner, I have several drip trail stains down the inside of the headlight lenses. I thought at first they were on the outside but they definitely aren't. Never saw this on any other of my Toyotas. I asked at the dealership and they said these are 'vented' so Toyota doesn't consider it unusual or a warranty item and there is no way to clean them inside. Seems like a poor design or a defect to me. Anyone else experience this? I'm concerned it will keep getting worse. Haven't used high pressure wash or anything either.