Cleaning must be done more carefully for microphones that do not have removable grilles, e.g., SM57, 545.
Using a damp toothbrush, hold the microphone upside down and very gently scrub the grille.
Holding the mic upside down will prevent excess moisture from leaking into the microphone cartridge.
This technique is also useful for cleaning the foam that covers the diaphragm inside an SM58.
Again, keep the mic upside down, and be very gentle.
In live situations with multiple acts, it may be desirable to clean the microphones between acts. Use a diluted solution of mouthwash (Listermint, Scope) with water. Using a toothbrush and holding the microphones upside down, scrub the grille of the microphone.
At the very least, this technique will make the microphones smell more pleasant to the performer. Also make certain the sound system is turned off before the cleaning begins!
Due to the more delicate nature of condenser microphones, never use water or any other liquid for cleaning purposes. Even a small amount of moisture may damage a condenser element.
For microphones with removable grilles like the Beta 87 or BG5.1, the grille and foam windscreen may be washed as described above.
Again, the grille and windscreen must be completely dry before reattaching it to the microphone. To clean a microphone with a permanently attached grille like the SM81 or BG4.1, use a dry, soft bristle toothbrush and gently scrub the grille.
Keep the microphone upside down so that loosened particles fall away from it. Take care not to let stray bristles get caught in the grille. This technique also works well for lavaliers and miniature gooseneck mics.
For condenser microphones that will be subject to harsh conditions, such as vocals and theater applications, it is advisable to use a removable external foam windscreen.
This will protect the microphone from saliva and make-up, and can be removed and cleaned with soap and water after the performance. Remember, never get water near a condenser element!
(Provided by Shure Incorporated.)