A bottle brush is made for use in bottles, drilled holes and other applications. It has either a wire or a plastic handle and the brush head is made to fit a particular size of bottle, tube, hole or flask. Since the necks of bottles are often narrower than the bases, a bottle brush usually has flexible bristles that allow it to slide past the neck into the base.
Scientists use bottle brushes to clean test tubes and flasks. One interesting type of bottle brush that some scientists use to clean curved flasks is one with a swivel head on it that rotates around the curved glass to clean it. Some industries also use bottle brushes to clean holes after drilling or even to spread or apply certain chemical substances. Bottle brushes are also used for cleaning air and water purification systems.
Bottle brushes are used in homes to clean baby bottles and items such as thermos bottles and vinegar bottles. They can also be great for cleaning narrow-necked vases. Some pet owners also use bottle brushes to clean water containers that attach to cages such as those for rodents. Brushes made to clean baby bottles may be brightly colored such as yellow or orange, but most bottle brushes are quite plain in color and design.
The narrowest bottle brushes usually have very flexible bristles plus a twisted-wire core with a top loop for easy gripping. A thicker type of bottle brush may have a sturdier plastic handle. Rounded, thicker bottle brushes may be good for cleaning items such as coffee cups.
Bristle materials on bottle brushes range from nylon to steel wire. The metal types are very stiff and made for heavy scrubbing, while the nylon type is usually much more flexible and made for lighter scrubbing. The food industry may use a variety of bottle brushes for cleaning equipment and in the United Kingdom a bottle brush may be known as a cook's brush or a twisted in wire brush. There is also an Australian plant, Callistemon, that is commonly known as the bottle brush plant as it features long flowers that have rows of spikes like a bottle brush.