Can someone use a cylinder on shabbos to wash fruit?
This depends on how the cylinder works. If fruit are soaked in the water, causing the dirt to rise to the surface, it may not be used on Shabbos. This would also be true for other similar methods of separation. However, if the method is only brushing the dirt off the fruit, it would be permitted to use, provided that this is done in close proximity to eating the fruit.
Sources: See Mishnah Berurah 319:28; Iggros Moshe, Orach Chaim 1:125.