Yep, boiling works too.
Just a note also - Mystery (AKA Apple) snails can't reproduce by themselves. They need a snail of the opposite sex with which to mate and lay eggs. Even if you have two of them of different sexes, they lay their egg clutches above the water, so you can always just remove it before the babies hatch. Other snails can breed by themselves and they lay their eggs at the bottom of the tank where they are almost invisible to the eye!
Just a note also - Mystery (AKA Apple) snails can't reproduce by themselves. They need a snail of the opposite sex with which to mate and lay eggs. Even if you have two of them of different sexes, they lay their egg clutches above the water, so you can always just remove it before the babies hatch. Other snails can breed by themselves and they lay their eggs at the bottom of the tank where they are almost invisible to the eye!