textScientists found that when mice sleep, their brains clean out the substance, beta-amyloid that builds up when people have Alzheimer???s Beta amyloidGood Night???s Sleep Cleans Out Gunk in BrainLOS ANGELES???When we sleep, our brains get rid of gunk that builds up while we???re awake, suggests a study that may provide new clues to treat Alzheimer???s disease and other disorders.