I've been using an ultrasonic cleaner for watch bands or rather bracelets. It works great! After 2 or 3 minutes it sparkles. You can get one from Home Depot or Amazon dot com. I have the SPT UC0609 which cost me about $35.
Link:
http://t.homedepot.com/p/SPT-Ultrasonic-Cleaner-UC-0609/202498189?cm_mmc=Shopping%7cBase&gclid=CPqS09ig1cMCFZSEfgodZG4AMA&gclsrc=aw.ds
Link:
http://t.homedepot.com/p/SPT-Ultrasonic-Cleaner-UC-0609/202498189?cm_mmc=Shopping%7cBase&gclid=CPqS09ig1cMCFZSEfgodZG4AMA&gclsrc=aw.ds