Here's what I have done in the past... do this at your own risk.

I take the rock/coral out

run it under cool freshwater in the kitchen sink, making sure to carefully inspect the polyps for any eggs before putting the colony back in the tank. I haven't had any coral losses yet.

the first couple of times I would cover the drain hole and have fun killing the nudibranches afterwards. My tank has been nudibranch free for months.

Dr. David de la Llata