It is essential to stop corrosion on the inside of your instrument. Don't submerge felts or corks on pistons. Allow the slides to soak for a few minutes. Be sure cover the cleaning rod completely as to not scratch the valve casing. One little dent in the valve casing can cause a costly repair since there is only one thousandth of an inch between a valve casing and the valve.
Trombone slides have similar clearances.
Do not touch silver sides of valve or place on a hard surface. If it becomes stuck, take it to your director or a repairman for removal using a special tool. You will damage the horn if you try to remove it yourself. Mouthpiece brushes are available at local music stores. Instrument maintenance kits are available at music dealers.