First you'll need:
*1 C of baking soda
*1/4 C of citric acid OR powdered preservative (which is what I used - it was easier to find)
*1/2 t of vinegar
*1 T of hydrogen peroxide
*Essential oil (to make it smell nice - I used peppermint)
*Cookie sheets or a hard surface out of the way
*Measuring spoons (yes, those are Mickey Mouse spoons, don't judge)
*Spray bottle (optional but recommended)
First, combine your baking soda and citric acid/powdered preservative in a bowl and mix them together with a fork, to remove any clumps.
Next, combine your vinegar and hydrogen peroxide in a glass and very VERY slowly add to the dry mixture. It doesn't have to be one drop at a time but constantly stir and slowly add the liquid until clumps start to form.
Then add your essential oils - I did about 15 drops and I think the peppermint permeated my nostrils because I can't stop smelling it!
Take your parchment paper and your cookie sheets (or hard surface) and place down enough parchment paper to hold all the tablets you'll be making. The original post says it makes 30 tablets but I made 112!
Finally, grab your 1/2 teaspoon, put some of the mixture in the spoon, and very gently tap it onto the parchment paper. You'll want to be very gentle so the mold holds and doesn't crack or crumble.
Spray equal parts vinegar and water onto the finished tablets (I used 1/3C of each and found it was way too much - had to toss most of it down the sink) and set them aside to dry.
The original post said to let them dry between 4 hours and overnight.
But since "patience" is not my middle name, I only waited 5 hours before giving them a try. They do fizz a little and they look a bit yellow in the water but they didn't smell up the toilet like I thought they would. When they're not in water, these smell freakin' amazing so keep them away from children, pets, and very hungry roommates! Please clearly label the jar you put them in and keep them out of harm's way. But in the toilet? You're definitely going to have to put in more than 1 to do any sort of damage.
TOTAL COSTS: About $15 to make at least 112
$2.99 for parchment paper from Target
$1.59 for baking soda
$1.99 for 32 fl. oz of hydrogen peroxide
$6.29 for Ball produce protector
Cookie sheets, measuring spoons/cups, and spray bottle on hand
13 minutes to combine ingredients
28 minutes to make 112
5 hours to dry (though some were still crumbling so overnight might be your best bet)
EASY-PEASY SCALE (1 super easy - 5 very difficult): 2 out of 5
You might have difficulty making the tablets, as they can crumble if you hit them against the parchment paper too hard but other than that, they're very easy to make. Now whether they work? That's a different story...