i soaked mine in 50/50 water bleach solution for a few days.
I then rinsed in copious amounts of running water. I then left in a large bowl of water to soak overnight for a few nights, changing the water daily. IMO it doesnt matter what you clean it with (within reason) the important part is to dilute it to a point where it doesnt harm the fish.
I did have to sluice out the central peice of the buble counter as some bleach had collected here - I have a limewood diffuser as a spare so wasnt too worried! It just took me a few days.
As a real 'anal retentive' guy I once knew said "the solution to pollution is dilution!"