If you’re looking to clean the inside of a whiskey barrel, there are a few things you’ll need. First, you’ll need some sort of solvent. Second, you’ll need some sort of brush or scrubber. And finally, you’ll need some hot water. To clean the inside of a whiskey barrel using solvent, mix one part solvent with three parts hot water. Soak the brush or scrubber in the mixture and scrub the inside of the barrel until it’s clean. Be sure to wear gloves and eye protection when cleaning the barrel, as solvent can be harmful if it gets into your eyes. To clean the inside of a whiskey barrel using hot water and soap, mix one part soap with three parts hot water. Soak the brush or scrubber in the mixture and scrub the inside of the barrel until it’s clean. Be sure to wear gloves and eye protection when cleaning the barrel, as soap can be harmful if it gets into your eyes. ..