Is it a problem to sort the dirty dishes in the kitchen after taking them off the table on Shabbos? For example, to put the big plates in a pile, small plates in a pile, cups all together etc. Thank you very much! Sara Kory Jerusalem
You should take plate by plate, from the top down, and then place each plate in its appropriate pile.
A similar question is raised concerning a pile of books: It is permitted to take a book from a pile in order to tidy them all up in their respective place?
The basic concept of borer applies to food, book, plates, and all items that are a “mixture” (see 319:3; Mishnah Berurah 15).
Some writes that a pile of books is not considered a “mixture,” since each item is large – and this can also apply to plates (see Yabia Omer 5:31; Halichos Olam 4 Beshalach).
However, most authorities agree that this is considered a mixture, and that it will not be permitted to sort it into different types and sizes. Rather, you should take the plates one by one, and after you have each plate in your hand you can place it where you want, without concern.
See Orchos Shabbos 3:20; Shemiras Shabbos 3:88; Or Lezion 2 p. 241.