Looking After Your Microphones
Obey the normal common-sense rules of electronic equipment care, e.g. avoid very high temperatures, dust, dampness, high humidity, physical shocks, etc.
Many performers think it's cool to swing the mic by its lead and generally throw it around the place. Unless you own the mic and you can afford to replace it regularly, don't do this.
Don't blow into the mic. The diaphragm is designed to respond to sound waves, not wind.
Don't tap the head of the microphone. This can damage the mic and/or speakers.
If applicable, turn mics off when not in use. Remove and replace batteries regularly. The action of removing and inserting batteries can help keep the contacts clean.
Don't subject microphones to volume levels greater than their design capabilities.
Always be careful with phantom power. Although it will not generally harm your microphone, it's prudent to play it safe.
Keep all leads safely secured. If someone trips over a lead there may be all sorts of problems from damaged mics to lawsuits.
If the performance of a mic deteriorates over time, it may be possible to have the diaphragm cleaned. You will need to talk to the supplier or manufacturer for details.