I found a fast and efficient way to clean calf bottles. Instead of washing them by hand, I took a 3/4-inch socket and duct taped it to the handle of the bottle brush. Then I took my 1/2-inch impact power wrench and hooked it up to my brush. I fill the bottles with hot water and a bit of dishwashing detergent. Then I put the brush into the bottle and use the power drill to rotate the brush at a high speed to clean the inside.