Welcome to R2R! I have let the snails be unless they are causing an issue. I have heard they can irritate some corals. Glue or cutting them off i believe are the only options.
I have given up on trying to remove these things. It takes one back luck to reintroduce them back in to your tank. I have read so many posts with differing opinions. Some say they will kill your corals while others say they will just irritate them. I have also read that SPS corals will grow over them and smother them to death. My experience is that they only irritate them.