I have used this large brush to clean out the inside of 1-gallon glass carboy bottles for about a year. We transfer milk from the plastic container to a glass jug, and when the milk is gone, I clean the jug between uses; so I use this a few times a month. This brush does well to reach the awkward spaces at the bottom and near the bottle neck so that no milk residue is left behind. Easy to clean; simply rinse in hot water, squeeze out the wool part, and hang to dry. Occasionally I spray non-toxic disinfectant (as I do on all of my brushes) to ensure it doesn't grow any harmful bacteria in between fibers. So far, the brush and its handle have no issues (no bristles falling out, no cracks in wood, etc.). A great, useful brush!