Using ultrasonic cleaner?

The other week I saw the small ultrasonic cleaner over at Harbor Freight was on sale (and still is)
http://www.harborfreight.com/ultrasonic-cleaner-3305.html

I've picked it up along with a bottle of their cleaning solution.
After a few runs on a few razors I have to say I'm disappointed in the results, and expected more of this, given what I've read here.

Am I perhaps using a poor cleaning solution, and if so, what would some recommendations be?
Could it be the cleaner is underpowered, or too weak to make much of a difference?
What about running multiple cycles to make up for this potential shortcoming?
Anything else that can be done to improve the outcome?

To add to this a bit, what about tossing my watch into this solution?
It is water resistant to 50m, as are most watches, but I'm not sure that is good enough grade to use in here.
Any other jewelry I should NOT drop in here? I'm looking mostly at rings, earrings and chains to clean.

Thanks B&B for all your advice!

Sparafucile said:

I have an L&R Q-90 ultrasonic, an industrial machine that costs about $250, so there is going to be a world of difference.

First, NO! Do NOT put your watch in - cavitation will cause the solution to flow into the watch.

I have read on more than one of the machinist's boards that the HF machines are actually not true ultrasonics, but more like vibrators; I don't know if that is true or not, but the $225 difference between a HF and an L&R means something, I think.

While I use some store-bought ultrasonic solutions, I find good old Dawn dish liquid to be all-around excellent cleaner, with a few drops of ammonia (if needed) in 110 degree water.

Jewelry, razors and the like clean up quite well after a few minutes in it.

Click to expand...

Absolutely correct....

I picked up this model at Harbor Freight, and it works great. http://www.harborfreight.com/25-liter-ultrasonic-cleaner-95563.html

I did not purchase their cleaner but did get one called Blitz from Amazon.com. So far I have cleaned my Rolex (no water leaked in), gold jewelry, diamonds, and some razors and all turned out great. In fact, my mother-in-law commented on how my wife's diamond ring sparkled.

Do not put any soft gems (pearls, emeralds, tanzanite, etc.) in the ultrasonic cleaner.