I would take them off of the zoa rocks. If there are also other rocks which don't have to many on, I would clean them also all off and put back in tank. You have to make sure you get them all. Depending on how many are on there it can be time consuming.
Something else you can do is take a rock (with no zoas) out of the tank every 4-6 days (you are trying to avoid a mini cycle) and get most of the biggest ones off then put it in a bucket/tub and start to cook it. Do this until you get them all out and cooking. You will have to leave some rock in the tank so you will need to clean some also. You don't want all of your rock out at the same time.
This is what I would do, but others might not have the time to do it this way.
Do you have a lot of rock in the tank?