I had a heavy aptasia infestation on my 60 gal reef tank about 2 months ago and initially tried peppermint shrimp. They just didn't do it for me. Then I read about lemon juice injections with a hypo and that was futile(the aptasia were too small and retracted when I tried to inject them, not to mention that I had over 100).
I know people on here have a lot of bad things to say about their LFS but I was advised to try a copperband butterfly and I have to admit...he was amazing. All of my aptasia was gone within a few days and the copperband has been a nice addition to the tank.
I looked through several cure-alls including Joe's juice, aptasia away, and even Berghia nudibranchs, and I was happy that I chose the Copperband.
Good luck with getting rid of them.
Steve