I bought a bag of Snake Away, but I haven't put it out yet. It's been a few months, and when I think about doing it, we have rain in the forecast. I have the same problem with spraying for weeds.
At my place, snakes got really bad because of all the mice I had in my chicken coops. We trapped and killed as many mice as we could, but we never made an impact on their numbers.
Then a couple calico cats showed up. I guess they where dumped, but I really don't know where they came from. We fed them, hoping they would eat the mice. Then a tom cat showed up and we didn't want him around, but he stuck around anyway, and our two calico's had kittens.
We now had a dozen cats, and that's when we noticed that the mice where not as plentiful as they used to be. The cat population seems to be holding steady at around 30 cats.
There hasn't been a mouse seen by us in years!!! Our snake problem just about totally disappeared. Not just around the house, but all over the land. I used to see them when bush hogging, but that hasn't happened in several years.
The cats wonder all over the land, and it could be that they have all the mice under control, which I doubt, but something has changed, and the snakes have been going elsewhere