You would be surprised how resilient they are. lol I had a bunch of rocks out of water for several weeks and laying in the hot sun as well and the aipastias came back.
The eventual way I killed mine was I nuked them with ammonia. What you could do is out the rock in a separate tank or container and dose with alot of pure ammonia. They will die off within like 3 days; BUT you will also kill the live rock. :-(
So I would first try to kill each one and see how you do. I use aiapastia X it comes with a syringe thing so you can jack each one.
180g- Mostly BIG fish and some coral. ~80g Nuvo- My coral tank with "happy fish"~ 90g- FOWLR Not the not happy type of fish~ 125g- Freshwater Malawi Cichlids ~10g- Nuvo- The refugees from the Ich of '18