Coral Acclimation

What is the most efficient means of acclimating a piece of coral without adding the bag water to your aquarium? Take for example, sponges, who can not be exposed to air. What have you found to be the best means of acclimation?

 

I use an extra overflow box to do all of my acclimation. With sponges I have the LFS add extra water into the bag, cut from the bottom, drain some water into the overflow until there is enough to cover the sponge, then drop the sponge in from the bottom. Then I remove some of the LFS water and start adding my tank water.