The directions that came with my ring say to soak it in a 1:6 dilution of ammonia in water. I then scrub it a bit with a tooth brush and it looks like new. I also took it to a local jeweler and they cleaned it for me for free but she told me that following the directions above work just fine.
This is how I was taught by my mom's friend who is a diamond dealer. 1:6 ammonia, let the ammonia/water mixture boil and then take it off of the stove and drop your ring in for like 5 minutes. Rinse it off or scrub it a bit with a soft tooth brush and you are like new!
I had the professional sonic cleaner and loved the way it came out - that is until I lost 3 side stones. My jeweler replaced the stones and told me that those cleaners can loosen the settings so I stopped using it.