Here is good advice from the International Musician: CLEAN YOUR INSTRUMENT REGULARLY...unless you like getting sick.
https://internationalmusician.org/ke...nd-instrument/
I use the Herco Spitballs once a week and they do a very good job for the tubes that are closest to my face (i.e. the leadpipe and all the valve tubes). Now and then you should also do a standard cleaning of the whole horn, but these Spitballs take just a couple minutes to use so you can manage it painlessly. The fluid contains alcohol and should help discourage the little germ thingies.
https://www.amazon.com/Herco-HE186-S...dp/B0002D0974/
If you are not familiar with Spitballs or are not sure how they work, here is a thread where we discuss them:
http://www.dwerden.com/forum/showthr...itballs-Magic!
For smaller instruments like trumpets, horns, or British-style baritone horns, Herco makes a smaller size:
https://www.amazon.com/Herco-HE185-S...dp/B0002E3GV4/