Victoria, if the wet jet takes the "throw away" swiffer cloths (and I think it does) then this will work on it.
Briana, it does stretch a lot. I think that even if it shrinks a little, like the dishcloths always do, that it will still fit as knitted. The stitching allows for a lot of stretch too.
Julie, this is the 1st thing I've made from this book. The patterns are very well written and easy to understand. I am just dying to make the little Edwardian dress and jacket for Miss Abby :)