If there are no fish in the tank
add one shot of vodka to the tank every second day for 10 days then do a water change vacuming the snails out
this should ...increase orgainic sugars...decrease available oxygen....fertilise your plants and ...kill the snails...maybe
If you have a single fish then dont do it
Whats wrong with snails anyway...they are self limiting...they get rid of the shite....and they turn your substarte stioping it from becoming anearobic.
Of course once cycled you coudl just add mollies and or platties or guppies and not feed them....you certainly wont have snails for long