I've played with these too. I used aloe gel and it worked great! I drew a few things on white muslin and have been tossing them into the wash periodically. I've probably washed them a dozen times or more now and the colors are staying very well! I heat set the colors with my iron; not sure if that's necessary but figured it couldn't hurt. I did some areas where I spread the color and then went back after it dried and put some sharper lines back in - all of those little details are still visible.
For brushes, I just used cheap kid's art brushes I had on hand. Probably could just use a finger if you're in a pinch and don't need fine detail.
They're fun!