The glass of the water is the eye, the dirt is the toxins. The dirt clouds the water just as toxins cloud the eye.
You'd be hardput to drain the dirt out of the glass, good news is that you CAN drain the toxins out of the eye. You can watch the meridian clear as the toxins leave the body.
(How'd I do there, Docta Dennis?)
God gave me really cool eyes. They are a dark blue-green, not blue hazel but literally peacock blue color. Over the years, I've developed a cat green circle around my pupil and the great color was fading. I read a very tiny bit on iridology and went to see what i could see in the mirror. Lo and behold!! My eye color has cleared tremendously and the green circle around the pupil is now nothing more than a few tiny tiny flecks of green.
To this day, a simple exam in a MDs office include looking into the eye with that lil light thingie. Today, they are only checking the health of the retina? Checking the organ meridians for problems is an all but lost art.