When I started playing I was taught to remove the valve and lubricate it liberally every day. I was taught that this not only lubricated the valves, it also help to flush impurities off the valves. I was also taught to wipe down my horn daily and to clean the inside by flushing the interior with warm water monthly. I don't clean quite that often any more, but I do a pretty good job of wiping my horns down daily and still oil my valves liberally on a daily basis. Yes, I buy oil in bulk, but it really isn't that expensive.