I just bump into this one
https://www.gardeningknowhow.com/plant-problems/pests/insects/organic-snail-control.htm

If you want to kill snails, you can do so with salt. Salt, for example, absorbs water from mollusks, which dehydrates and kills them. Sprinkle the salt directly onto the snails or use a thick layer of it to create a barrier. Be aware, though, that salt can harm plants and other animals.
Also gritty substances will cut/injure snails.

Snail traps – you bury them in the ground to the level specified and put beer in the bottom – the snails crawl in and drown.
There are also pet safe snail baits that have taste deterrents and also require large amounts to cause any issues. If you use very sparingly you should be fine. Alternatively – place in a metal crate so pets can’t access but the slugs / snails can

Beer in little containers set in the ground around the area you want to protect works well.

Small cups of beer set into the ground. Attracts and kills them. Coffee grounds and egg shells are spose to deter them

They don’t like grass cuttings or sawdust, try placing either of these around your plants. They also make a great compost and help keep moisture in the ground

If you have a coffee machine or perculator you can use the used coffee grinds to sprinkle around the plants, also crushed egg shells or salt. Snails don’t like to slide over gritty sharp things

I put a trail of salt around the plants. Watch them sizzle

I had a major problem with large garden snails that would all emerge when a bit of damp weather came about, I did not want to use chemicals due to animals and twin 3 year olds, however my problems were solved when the boys decided that they wanted to catch the snails!! they did, they caught about 4 large buckets in a couple of hours, kept them busy and they were so excited, they did this everytime a bit of damp weather came about and within about a month we had minimal snails in a very large backyard, only problem I had is how do you get rid of heaps of live snails, eventually mum told me to pour hot water over them, this worked but seemed a bit cruel, apparently you can cover them with salt and that will kill them as well, but basically for us it was collecting them and destroying them, time consuming if you don’t have slave labour but it was extremely effective.

Sandpaper. Or, and I know this sounds odd, look up the DirtGirl World website, one of her episodes had some natural remedies for snails, but I can’t remember them right now.

thanks mums

Salt will kill them and deter them