Cleaning Brushes by Owala. Details:The Owala Bottle Brush/Straw Brush cleans every nook and cranny of water bottles, thermoses, and drink tumblers with its clever 2-in-1 versatility. The smaller Twist N' Hide straw brush is ideal for cleaning inside bottle straws and other hard-to-reach places; when not in use, it nests inside the handle of the larger bottle brush, which tackles bigger cleaning jobs. The bottle brush’s removable head is made of firm bristles—stubborn residue doesn’t stand a chance. A convenient hanging loop helps keep the brush tucked tidily away when off duty. Dishwasher safe.