Comments about Walgreens Warm Steam Vaporizer, 1 ea:

Yes, as the other reviewer said, it leaves black stuff behind in the water. That's normal.

I've had this humidifier for about four years now and I love it. It's so simple.

My only complaint is that it's difficult to pour ALL the water out when you're cleaning it, so black stuff gets left behind even if you rinse it four or five times. It doesn't seem to hurt anything though.

I also wish it held a little more water because I usually have to add more after about six hours so it doesn't get me all the way through the night.

Comments about Walgreens Warm Steam Vaporizer, 1 ea:

Worked well from the start, although we had to add a little sale to the water as suggested in the manual. However, now there is some black stuff showing up in the water... I would guess soot. I am going to run some clean water through it and see what happens, if it keeps up it will have to go back.