i have used vinegar for my small anemones. i just put some in a syringe and then turn all of the current off (powerheads/skimmer), let the water become very still, then slowly release the vinegar near the anemone. the longer you can keep the vinegar in contact with the anemone, the better. most of them die after this treatment, but some of them come back after a couple of days. (i just treat them until they die) i wouldnt recommend this if you have corals or other life forms very near the pest anemone, as this will probably hurt those life forms. good luck.