We use a shop brush on our Marmoleum. A small piece of the thinnest flexible cutting board makes an excellent "dust pan".
We have an astroturf mat just inside the slider, which catches an amazing amount of debris. The toilet, which also functions as a seat, is right beside it, so when our boots are wet or particularly filthy, we can remove them before stepping off the mat.
Once a week or so, I wipe the Marmoleum with a wet paper towel.