Has anyone here used diatomaceous earth?

Yes indeed, it's a great cleaner, as well as an excellent filtering base for water treatment.
It's also in many products like toothpaste ans soap.

I heard about the "dirt" awhile back ..I have a farm, and it's an awesome "sensible" dewormer. I am stocking up on it now, because I think it would be awful if animal owners were denied access to it because of some new liberal legislation.
It scratches silver and copper but it worked on a rust stain on a counter in my bathe.
I am enjoying this site. It reminds me of Mother Earth News *before they got "managed" by greenies.
I always considered myself a "tree hugger" until the media forgot that we are all individuals and don't need to be defined.
Thank you for commenting.

*my opinion

I had to ponder this for awhile, I thought you meant it killed earthworms.

I had no idea it killed intestinal parasites, but it makes sense.
I know if you pulverize it into a powder and spread in on an ant line, it locks up their exoskeleton so they can't move, like sand on bearings. 
And to think, it's nothing but microscopic organisms that lived millions of years ago.

I use it in my garden on my plants. Kills bugs, but you have to reapply it after each rain. I don't use chemicals so this helps. Also use Pulverizes Clay on my apple fruit trees, same thing though after each rain you have to reapply.

It breaks up clay?
I've used gypsum, or old sheet rock to break up clay, but I'll have to try diatoms next time.
Thanks for the tip...

I miss typed there. I uses pulverized clay on my apple and other fruit trees. The bugs either don't like it or can't get to the green. I mix it up in a sprayer and just apply it. It's available at most organic gardening web sights as is the Diatomaceous Earth.