The hungriest loach for snail removal is a clown loach (chromobotia macracanthus). See attached image. If you can find three or four small loaches only a year old. They really do dig around endlessly munching on snails. In two or three months your aquarium will be snail-free. But clown loaches also disturb plants. Not as bad as some cichlids, but just be prepared to repair any damage done during the night. They also are not small fish meant for the community aquarium, unless you keep larges species. Given enough room -- and time -- they can easily grow to one foot+ in length.
Another option, if you plan on removing all fish, is to add a tablespoon per gallon of alum to your tank. The snails should be gone in about a week (they die a miserable death of contorting up in their shells). Then do a complete water change two or three times a week to eliminate the alum. Alum does not leave trace metals like copper or stuff like iodine. If you're interested in keeping the plants in place, alum will not harm them. It might stress them a bit, but it's a temporary measure. Don't leave them soaking in alum-laced water for more than five or six days. Eventually what trace of alum is left will be negligible and of no danger to new fish you plan to introduce. But as a caution, when you do introduce new stock first add some test fish such as feeder guppies and a couple of zebra danios. If they are thriving after a week you are good to go.
Personally, I'd look into the clown loach approach. They're cute, attractive and somewhat personable. Just don't feed them every day (every other day is fine). They'll be hungry enough to feed themselves if you have plenty of snails.
Good luck.