there are several methods that can be used. How big is your tank, how new is the tank. If you have rock and nothing else, then what i would do is remove all the rock and just soak in RO water without salt, and "kill" the rock, then add salt and let it recure. This will kill the glass anemones off and once recured, there will be no difference except you will be backed up about a month.
joes juice works well, lemon juice. kalkwasser paste, boiling hot water. Keep in mind the joes, lemon and boiling water need to be injected into the base of the apstasia inorder to be effective. Hyperdermic needs, small ones like what the vets use work very well.