Bronze age faster than brass and sterling silver, so it's important to wipe it clean often.
Brass age faster than sterling silver, but if you wear the piece daily, it tend to keep it's golden tone! Wipe to clean.
Sterling Silver is softer than brass and bronze. It oxidize itself as time pass by. I personality love the aged look of sterling silver, you may simply wipe it (or clean with tooth paste) to make it shine again!
Keep jewelry pieces away from any chemical subjects!!
* hair spray =(
* soft cloth =)