Review (4/5): Works great
"Jeff's Wife" - I've used the white name brand for years and some store brands but not the charcoal ones. These work just as good as the others, although I'm not sure if the charcoal really makes a difference.
The description photos show slits in the strip but I haven't seen them in mine, not a big deal but they do serve a purpose. There is quite a bit of black residue left over (there's also residue left over when using the white ones, the black is just more visible) but it rinses away easily with warm water.
I'm very happy with these.