I like to thoroughly clean out my horn before a performance, which usually means removing the slides, submerging the gutted horn in lukewarm water, a little gentle scrubbing with dish soap, cleaning and snaking the valves seperately, snaking the horn, emptying the water out of the vavle-less horn (which is probably the longest and most tedious part of owning a horn), drying and shining. But I don't believe rotary valves can be removed, and I'm always hesitant to do this because I'm concerned it may damage my valves. Will it, or is this safe to continue doing? If not, what can I do to protect or remove the valves before I "bathe" my horn? Thanks.
Horn rotors should be pulled about once a year and cleaned, some players like to have this done every 6 months. This is something that is best left to a professional repair person( and you can have the entire horn cleaned at the same time). Rotors can be removed at home. Their is a good video on youtube, by the horn professor at the University of Louisiana showing this process, however if a good repair shop is nearby, i suggest letting them do the work. You should get your horn professionally cleaned once a year anyway. Hope this helps. Jason.
When I was a high school kid (in the 1960s), my band director gathered all the horn players together in the summer before school started. We took apart our valves, cleaned them in HCl and reassembled & lubed them. They worked just fine. We were so proud of our work.
After I came back to horn as an adult, I bought a used horn. After a few weeks, the valves started sounding a little "scratchy" and moved slowly. So I took them apart, confident that I'd be able to put them back together as I did when a teen. The were quite tarnished, so I cleaned them gently with Brasso. To my horror, when I tried to reassemble them, they got worse! I tried everything I could think of, but they got worse & worse & one totally froze. I finally ended up taking the horn to a pro. technician to put together for me. He told me that modern horns have tighter fitting valves, so they are very difficult to put together properly. I will NEVER take my valves apart again. It's not worth the risk.
Valerie has a great point, while the valves may be removed, I do not recommend doing so. I practiced removing and reassembling valves for a class in college. We used old Conn 6d's. I have never attempted this on the newer modern horns and let the experts take care of the horns I currently play. As for your question of bathing your horn harming the valves,it will not. Just be sure to properly oil them after every bath.
If I'm not in too much of a hurry, I like to leave all my valves off the horn overnight after it's cleaned so it can dry, then lube it the next day. Then I pour in a couple tablespoons or more of Ultra Pure Lamp oil & twist it round every which way while flicking the valves so the entire inner surfaces are coated. I don't remember who first told me about Ultra Pure Lamp Oil, but it's a very nice valve oil and completely odorless. I use STP oil treatment for my slides and 3-in-one oil for the rotor spindles.