Blue Wave from the house of Jöst. The Blue Wave stands apart from conventional melamine cleaning sponges thanks to its unique waffle. The waffle reinforces the sponge’s structure, resulting in an enormous increase in service life. This cleaning sponge will remove all stubborn soiling on smooth and hard surfaces, such as heel marks on floors, pen marks on desks, calcified surfaces, dirt on car windows and much more using only water – the Blue Wave’s eraser effect makes the use of chemicals unnecessary. Do not use the sponge on high-gloss polished surfaces.