If you don’t have a way to weigh it, try 2/3 cup (110 g) of each. If you don’t have cornmeal, try using flour instead in the same proportions. [1] X Research source The plaster of Paris will get harder in the rats’ stomach, eventually killing them.

If you don’t have milk on hand, you can just use water. The milk will give it more flavor to draw in the rats, but most likely, they’ll still eat it just for the cornmeal or flour. [3] X Research source

If the mixture isn’t sticking together and you see loose powder still, add more water or milk, a spoonful at a time. You want it to form a dough you can roll into balls like clay. If it seems too liquidy, add more plaster and cornmeal/flour in equal parts, only adding a spoonful at a time until you get the right consistency. [4] X Research source

If they’re not, you may need to move the balls. If the rats still aren’t interested, you may need to make a new set.

You can also just mix sugar and baking soda together. You can substitute cornmeal for the flour or hot chocolate mix for the sugar. To make the mixture more homogeneous, pulse it in a blender so it sifts together better. Another option is to mix 1 part baking soda with 2 parts peanut butter.

Look for rat droppings (small, oblong feces), as the rats are likely to be nearby. The baking soda mixes with the acid in the rats’ stomachs and causes a buildup of carbon dioxide, which eventually kills the rat.

Make sure to put at least 1/2 cup (50 g) in each bowl so the rats will really chow down.

Rats are drawn to the food, so they’ll come chow down on the dried flakes. Then, when they drink water, the subsequent bloating will eventually cause their deaths.

Alternatively, try adding 1-2 spoonfuls of sugar to the mix to make the food more enticing.

You’ll need to spray the area again from time to time; try to do it at least once a week. Peppermint may also deter spiders. Alternatively, dip cotton balls in peppermint oil and place them in the areas where you’ve seen rats.

However, keep in mind that this can also cause stomach issues in other pets, such as cats and dogs. [12] X Trustworthy Source American Society for the Prevention of Cruelty to Animals Leading organization dedicated to the prevention of animal cruelty Go to source

You may need to renew this when it rains if you’re using it outside.

Never mix ammonia and bleach, as it creates toxic fumes.