to be effective they should be cheap and should stay effective even when wet

Pellets (Many different brands):

These are the classical rabbit food look-alike metaldahyde pellets they are inexpensive (compared to more desperate techniques), readily available‚you can buy them most places you can buy cornflakes or fertilizer‚and it's not a much more effective than corn flakes or fertilizer for killing snails. The pellets lose there effectiveness when they get wet (remember if you put them where snails go they will get wet) and they look like food even to non-snails. Some forms have insecticides that may kill a variety of other unintended victims.

Pellets, bulk packaging:

I have recently found this type of pellet in large twenty-five pound bags (for about ten to twenty dollars) that survive well in moist conditions. This is enough for me to treat my whole yard at once. If you use these pellets, cover the whole yard, and repeat the treatment after twenty-one day - the presumed length of the snail reproductive cycle - you can achieve a fairly sucessful yard wide control of snails. When snails come back you can treat them more locally and you won't be overwhelmed by them. I don't know what the long term effect of this much metaldahyde would be and I'm not sure how this technique will work during the rainy season.

Granules(That's It):

This is a more effective dry bait. It looks like coarse salt or sand which makes it looks less food like even to the most enthusiastic and gullible of pets, it has the highest metaldehyde concentration of commercial products (making it last longer, even when moist). It is however more expensive and much harder to find. You will have to go to a nursery or garden shop for this product.

Thick Black Goo(Deadline):

This product also uses metaldehyde, is very resistent to moisture‚It will survive during the rainy season when snails are their worst and won't be washed away by you sprinklers the rest of the year, and finally nothing living would consider the black slime pallitable. This product is almost as widely available as the pellets and much more effective. It is, of course, expensive but a penny's worth of black goo will kill many more snails than a penny's worth of pellets. You still won't conquer your snails but with this product you will be able to use bait to keep snails from a particular area by surrounding it with black goo. It can leave a stain on concrete

Area Spray:

This expensive, and relatively complicated technique is ineffective for two reasons, it doesn't kill snails for a long enough period and is too expensive to allow repeated or wide spead applications. During the rainy season, it will take longer to mix and reapply than it will for the snail to replace their dead.

Beer(Coors, Brew 102):

You probably shouldn't use good beer for this. It is easy enough to feel foolish while gardening, and while growing plants for snails to forage upon is maddening; it doesn't feel any better to realize that you are supplying them with beer to wash it down with. It might be more satisfying to buy good beer, drink it yourself and forget about the snails.

Copper Foil:

There is a theory(superstition?) that snails won't cross copper, it sounds like witchcraft to me, but since I'm already desperate, why not? This technique is best for trees. I have tried this around the trunk on apricot trees but I have had problems keeping the copper foil in place and keeping the snails from climbing into the tree from the tips of drooping branches or from near by trees or shrubs.

Diatomaceous Earth:

This is another superstitous belief in my opinion. I haven't noticed any reluctance on the part of snails in the matter of crossing a line of diatomaceous earth, especially when it is wet. At least this method doesn't seem to do any harm, not even to the snails.

Row Cover:

This has been one of the most effective techniques for vegetable crops. I use it to protect lettuce for the entire season and for beans and tomatoes I use it early in the season while the plants are small and it is still wet. For this to work well, you should turn the soil before you plant, (this is a good time to fertilize if this is going to be done) this reduces the snails that could hatch out from the soil inside your row cover. Another point is to use either bricks or 'earth staples' to secure the entire perimeter of the row cover. If snails can find a way in, they will.

these techniques may have some theraputic value

Predatory Snails (Decollate Snails):

I have tried Predatory snails as a snail control. The advantage of a predator spending its day hunting snails appealed to me as did the irony of having the snails eaten by other snails. I had read that these new snails were voracious predators and didn't eat garden plants at all. When not ravenously devouring brown snails, I was told, these snails were scavengers and only ate dead plant material. These snails were shy and tended to roam less than the brown snail and so would be less likely to be killed by snail bait intended for the brown snails. Well this is what I have observed: There has been no observable 'control' of the brown snails‚I still have a King's ransom in snails in my backyard. I have never seen a predator snail even cross with a brown snail; shy probably. The new expensive predator snails seem to be more likely to be killed by the bait than the intended target‚shy and stupid? I now have two kinds of snails sliming their way around my backyard, only now some of them are SNAILS I BOUGHT! Actually I've now seen a third kind of snail, much smaller and shaped like a ram's horn or flattened coil. I don't know what this new snail eats but at least I didn't have to pay for them. Also, I think they may be a little shy.

Pick & Stomp:

This can be a simple and effective technique particularly if you have many children to help. One way to do this is to simply pick off every snail you see and smash it. Be thorough, I've seen snails with smashed or partly smashed shells survive to grow new shells and go on their merry way. The more people who help the better‚this where the children come in‚make it a competition to see who can get the most snails. You probably shouldn't wear you best shoes to do this. The squemish can use a recloseable bag or can to collect the snails then close it up and put it in the trash. When the novelty wears off you will probably need to offer a bounty on the snails. My advice to you is to set the price low or you will end up bankrupt.

Pick & Throw:

A variation of pick & stomp, you pick the snail and throw it out of your yard. This technique, while satisfying has several obvious limitations: 1) the snails crawl backămany of your snails came from next door originally and already know the way. 2) If your neighbors catch you doing this, they will probably take it the wrong way, and may even return the favor(and snails). 3) If you hit your neighbor with the snails they will inevitably be even less charitable about the incident. 4) Even Bret Farve would run out of arm before he ran out of snails; you might as well try to throw all the dirt out of your backyard, at least it doesn't reproduce.

Ammonia:

This is a technique I learned from my Dad. You use ordinary household ammonia cleaner‚don't get a brand name‚ you want the cheapest, largest container you can get. (Remember there are a lot of snails out there.) Put the ammonia in a household pump sprayer and go find some snails! To be effective the ammonia must be sprayed directly on the snail. You will be able to tell when you hit it, it will shrivel up and ooze green slime. If it's climbing on something it will fall off and die. This technique is tremendously satisfying if you really hate snails but it is not for the squeamish. This is another job for tough minded little boys and girls Calvin would love this but Barbie would not.