Laws of Muktzeh on Shabbos
2. [The following (and anything similar) are considered muktzeh and thus
may not be moved on Shabbos]:
i) Food that is totally unfit for human consumption in its present state,
even in extreme circumstances, because it requires cooking; although the
food is suitable for animals or dogs in its present state, since it is
meant for human consumption at a later date, it is not considered prepared
for the use of animals or dogs (1).
ii) Articles that are not useful for any purpose on Shabbos, for example:
pieces of wood , feathers, animal hides, wool, flax, animals, even
household pets, nut shells, egg shells, hard bones that are not fit to be
eaten even by dogs, doors or windows (which are forbidden to be attached on
Shabbos), and broken utensils that are no longer fit for any purpose (2).
Broken glass may nevertheless be moved if it is lying in a place where it
can cause damage.
(1) Here we see the principle that if something is designated for a purpose
which cannot be achieved on Shabbos (in this case, because cooking is
prohibited), it is considered muktzeh, even if it is suitable for another
usage for which it was not originally designated. In HY 88:1, we saw that
food which, before Shabbos, was designated for sale, is not considered
muktzah; this is because food that is fit for human consumption is vital
for one's life and a person never totally abandons the possibility of
partaking of it should the need arise ("Muktzeh: A Practical Guide" by Rav
(2) Something which has no inherent function in its present state (and
therefore is not defined as a "Keli") is called "muktzeh machamas gufo"
("inherently muktzeh"), We shall see later in the chapter, that, in certain
cases, one may move a mukzteh item in order to use the space it occupies
("tzorech mekomo") or to use the body of the object itself ("tzorech
gufo"). However, items which are classified as "muktzeh machamas gufo" may
never be moved on Shabbos, even where monetary loss is involved (See Mishna
Prior to the onset of Shabbos, one may designate objects such as sticks and
stones to be used for a specific purpose (like a door stop), thereby
turning them into functional objects, and removing their muktzeh status. To
designate an object for permanent use, a mental resolution is sufficient;
for temporary designation (that is, just for one Shabbos), one must make a
physical change in the object (See Shulchan Aruch 208:21-22).