Before I learned proper dental hygiene, I cleaned out my trumpet with detergent, warm water, and a tubing brush about once a month, because it needed it. Now that I brush and floss at least twice a day (usually planning this with whenever I'm ready to pick up my horn), I have yet to brush out any of my horns. I lube the valves before use, and I periodically check the inside of the tubing with a flashlight to monitor any discoloration, buildup, or corrosion. There isn't any. I use Herco Spit Balls once a week, and this, combined with dental care, has kept the insides of my horns absolutely clean.