This is one of the first things I found, and the product that has required the most experimentation. We have used detergent “cubes” in our dishwasher. They are more expensive but I just like the simplicity. So when I saw a recipe for dishwasher soap cubes, it looked kind of fun.
The first mistake that I made is that I bought ice cube trays that made cubes that were too big for the soap compartment in my dishwasher. I didn’t think this would matter because the blogs I read said to just toss the cube in the bottom of the washer. Unfortunately, my dishwasher has a rinse cycle that would dissolve all the soap and then drain it so there was nothing left by the time the wash cycle started. This little problem requires me to stand next to my dishwasher while the rinse cycle goes, then open it up after it drains and as it is filling back up for the wash cycle. Not only is this a pain, but I have some sort of attention deficit disorder and NEVER get this right. It took me 3 tries and 3 cubes to get it right one morning. Long story. The solution is to buy small ice cube trays and test them first. I made ice cubes in the 2nd set of trays, then took an ice cube and made sure the soap compartment would close. Now I just have to use up the first batch that I made. If you don’t want to mess with this, I will give you the powder alternative at the end of this post.
1 cup Borax
1 Cup Super Washing Soda
1/4 cup Epsom salt (or kosher salt) – this is a natural “scrubber”
1/2 cup lemon juice
Mix the dry ingredients first. Then mix in the lemon juice so it is a wets all the dry ingredients and is mixed well. Put scoops of this in ice cube trays and press down. Let the mixture dry overnight. I got over-eager in the first batch and tried to take them out after a couple of hours because they seemed dry on the top. Those crumbled a lot. The ones that I let sit overnight popped out of the trays very easily the next morning and didn’t crumble.
After using this for a few loads, we noticed that there was a film on the dishes, especially the plastic ones. So I researched some more and discovered that vinegar is a great rinse agent. I poured some in the rinse agent compartment in my dishwasher and the next load came out perfect.
If you want the dry powder alternative, use ½ cup of citric acid (found with canning supplies at the grocery store) instead of the lemon juice. Citric acid is about $3 for 1 cup so it is more expensive than using lemon juice which I always have on hand.
September 2013 Update: I am still looking for a recipe that really works. I have seen lots of posts out there with this (or a similar) recipe and they claim it works great. But even with vinegar in the rinse compartment, my dishes still had a film. I really like sparkling glasses, so am not using this anymore.