Very effective, but the smell is so strong that I had to use it only outdoors.

Whatever removes the flux, removes it, but still leaves something on the board. However, I am sure that what it leaves behind does not cause the damage that the paste (flux) can cause in the long run. It also has a strong smell, I personally like the smell but others do not. The smell fills the entire space. It is also very effective for removing glue, etc