"Irish Spring and a cheese grater. Apparently squirrels hate the smell of the soap, so they'll stay out of your garden. "
I saw this on Pinterest last week and was rather curious. After a bit of a search on gardening forums, the majority of them say it doesn't seem to work. It's been tried on everything from squirrels to deer and even rats, but for the most part it doesn't work as much of a deterrent. I also wonder about the effects of having shaved soap in my flower beds or garden as I wonder if the various additives could affect the plants at all.
Over at the source of the image, The Cape on the Corner, I decided to ask and see how it was working for her. She let me know that she didn't believe it was all that successful for her, but she only tried it once.
So what can you do if you're being harassed by squirrels? My biggest suggestion is to try to set up a squirrel feeder if you can. Generally if they have a steady source of food, they'll leave everything else alone. If that's not something you're interested in, the Humane Society has some great suggestions on what you can use around your house and on your plants to prevent squirrel damage.