The Pin I saw originated at Homemade Soft Scrub Live Renewed, and was a guest post by Stacy at A Delightful Home. She adapted her version from the recipe for Earth Paste in Clean House, Clean Planet by Karen Logan (pg. 243). (If you would like the original recipe/amounts, you can click on one of the links I just listed.)
I only had one problem with the recipe - it calls for both vinegar and castile soap. Any first year chemistry student knows that acids and bases cancel out each other. Vinegar is an acid, and castile soap is a base. So if you use both, you're going to lose the effectiveness of each - so why would you use both in a recipe? There's even an article on Dr. Bronner's website about it (that company makes castile soap).
So I started out with a really small batch, because I would hate to have to throw away a ton of it if it didn't work - and I left out the vinegar. Here's exactly what I used:
6 TBSP. baking soda
2 TBSP. Dr. Bronner's Peppermint castile soap
1/2 TBSP. water
First, I mixed 6 TBSP. baking soda & the 2 TBSP. castile soap together, stirring gently so the soap didn't get all foamy.
Then I gently mixed in 1/2 TBSP. water.
The consistency is a little thinner than store-bought Soft Scrub, but you can add more baking soda if you like.
To test it, I used a little with a regular O-Cel-O dish scrubbing pad in my kitchen sinks. I tried to take a picture, but for some reason, the camera refused to focus on the sinks, so you'll have to take my word on the results!
It worked pretty well! In the interest of full-disclosure, my sinks weren't that dirty, but it removed what was there - and the best part is that it rinsed completely in one rinse - without any residue! The second best part was the smell - love the peppermint! I know castile soap can leave a residue, but I think the baking soda may have eliminated that - or at least I couldn't see or feel anything on the sinks.
According to the original post, you should make this in small batches because it can dry out and harden when stored. Keep any remaining mixture in an air tight container. They also said that their recipe (which was double mine) was good for 2-4 uses. They must use a lot more soft scrub than I do because the small batch I made will probably be good for at least 4-6 uses for me - but I only use it on my kitchen sinks.
The verdict: Pin-worthy - but leave out the vinegar!! I will definitely be making this stuff! I also have an idea that I want to test that may make this even more economical. I'll post about it when I get a chance to try it.