An ultrasonic cleaner will get your diamonds sparlking like MAD! Especially if you use hot water, some mr. clean and some windex in the machine. I usually put mine in for a cycle or two and then clean it with a soft toothbrush.
You can get ultrasonics just about anywhere, sharper image has them, and I'm sure you could find them at a home store as well.
For quicker touch ups, I LOVE Connoiseeurs jewelry soap and gel. Both work great.
Thanks for all the hints girls, I'm not totally sure what an ultrasonic is but I'll look into it!
I actually read one in a magazine last night about using vodka, anyone tried that?
I drop all my jewelry into a cup of 3/4 hot water and 1/4 ammonia. Let it soak while I do whatever {brush teeth, etc . . . } and then scrub w/ a toothbrush.
It's cheap and as effective as anything else I've tried, and I've tried everything! I have the Ultrasonic cleaner as well and you can smell th eammonia in their little solution when you pour it in