"Just use a pack of Lemonade Kool-aid to clean your dishwasher"
Before you all click away thinking I've lost my mind--stick with me on this. It is a good idea. Sort of at least. Why? Because of the citric acid found in the drink mix.
So first off, let's talk about what is citric acid. It's an organic acid that is oftentimes is used in foods to create that 'zing' or sour taste, and also as a preservative in things like canning fruits. (It can also be used in everything from bath salts to drink tablets to help create fizz)
In cleaning it is used as a descaler and very useful in removing lime and mineral buildup and softens water. Which is why it works so well in your dishwasher. Often times, especially if you live in an area with naturally mineral rich water or hard water, you dishwasher can get clogged over time with build up.
In my research I was curious though as to just how MUCH citric acid is in Kool-Aid. For all I knew it was just a small amount, making this worthless as you'd need to add a lot of packets to get the desired effect. But I found several science papers on the content of citric acid in Kool-Aid. Who knew? Apparently it's a common item in high school chem classes! These papers state that the content of citric acid and ascorbic acid (vitamin C) is 100:1 ratio. The size of a package of Kool-aid is .23 oz, and costs about 10-20 cents a pack.
Not to mention you can buy straight-up citric acid online for around $16 for a two pound jug. Doing the math on that, that is the same as spending around $27 for the same amount in the Kool-Aid packs, and without all the other stuff (flavors, dyes) that are found in the mix. So you're actually getting a far better deal buying just citric acid than you would buying the Kool-Aid.
If you've ever used lemon juice to descale your kettle or coffee pot, you can see how powerful citric acid is in cleaning. So yes, this is a good idea, and yes, Kool-aid will work, but you're better off keeping Kool-Aid on the shelf and just reaching for pure citric acid instead. Most grocery stores carry it, if not by name then as "Sour Salt", it's often kept in the canning section of your store. And you can use it elsewhere besides your dishwasher--you can even mix some with hot water in a zip top baggie, place over your clogged shower head and tie in place. Leave over night and it's build up free by morning. Anywhere you get mineral build up can be cleaned with citric acid (think of if it as a more natural CLR for the house).