Kelim she-melakhtam le-isur are objects normally used for activities that are prohibited on Shabbat. Some examples are hammers, scissors, needles, pliers, and phone books. Since they are designed for things that are prohibited on Shabbat, they are muktzeh. Nevertheless, since they can be used for permissible activities as well, one does not put them out of his mind completely over Shabbat. Therefore, the Sages established an intermediate category for such items. On the one hand, they are muktzeh, and one may not move them even if they were left in a place where they are likely to be damaged or stolen. On the other hand, one may move them in two cases: le-tzorekh gufam or le-tzorekh mekomam (SA 308:3).
Le-tzorekh gufo (pl. “gufam”) means using the kli she-melakhto le-isur to do something permissible, like using a hammer to crack nuts, scissors to open a milk bag, a needle to remove a thorn, pliers to open and shut a faucet whose handle is missing, and a telephone book to look up an address. If the same goal can be attained without using a kli she-melakhto le-isur, it should not be used (MB 308:12).
Le-tzorekh mekomo (pl. “mekomam”) means moving the kli she-melakhto le-isur to use the space it occupies. Thus, if such an object was left on the table one wishes to eat at, the bed he wishes to lie in, or a chair he wishes to sit upon, he may move it. Similarly, if such an item was left on the floor in a spot where people will likely trip over it, one may move it. If the door of a washing machine was left open and is getting in the way, it may be closed. If a kli she-melakhto le-isur makes it difficult to open or close a window, it may be moved.
Once the kli she-melakhto le-isur has been picked up, whether le-tzorekh gufo or le-tzorekh mekomo, one may move it to where it will be safe (SA 308:3; section 15 below).
Other examples of kelim she-melakhtam le-isur are: pens, pencils, pencil sharpeners, paintbrushes, lined paper, accounting forms, sandpaper, carbon paper, candles, matches, nails, and cigarettes.
Some kelim she-melakhtam le-isur, such as an artist’s knives or a diamond cutter’s tools, are considered muktzeh maĥmat ĥesron kis, since their owners are careful not to use them for other purposes. The laws pertaining to them are stricter – they may not be moved even le-tzorekh gufam or le-tzorekh mekomam (see section 4 above).
Electrical appliances such as fans, washing machines, refrigerators, and other appliances with no incandescent filament are considered kelim she-melakhtam le-isur. Electrical appliances with a heating element or incandescent filament, such as light bulbs, heaters, radiators, and warming trays (platas) that were on during bein ha-shmashot on Friday (when Shabbat started) are considered muktzeh maĥmat gufam and may not be moved during Shabbat even le-tzorekh gufam or le-tzorekh mekomam. In contrast, if they were off throughout bein ha-shmashot, they are considered kelim she-melakhtam le-isur and may be moved le-tzorekh gufam or le-tzorekh mekomam.
. Even though one may not move a kli she-melakhto le-isur to prevent it from being damaged or stolen, one may use a halakhic loophole (ha’arama) to accomplish this goal indirectly. In other words, one may pick up the kli initially le-tzorekh gufo or le-tzorekh mekomo and then put it down where it is protected from the elements and from theft (MB 308:16; Yalkut Yosef vol. 2, p. 412).
. In contrast, any item that is not a kli but is used for an activity prohibited on Shabbat, such as firewood, kerosene, bar soap, thick liquid soap, laundry detergent, and shoe polish – is considered muktzeh maĥmat gufo, and thus may not be moved even le-tzorekh gufo or le-tzorekh mekomo (MB 308:34; Orĥot Shabbat 19:7).
. An incandescent filament that was on throughout bein ha-shmashot has the same status as a flame that was lit throughout bein ha-shmashot – it is absolutely muktzeh, as explained in SA 279:1. However, some maintain that an incandescent filament differs from a flame, because flames are not normally moved, whereas devices with incandescent filaments are normally moved. Therefore, according to them, the status of the appliance is that of a kli she-melakhto le-isur (Ĥazon Ish 41:16; Igrot Moshe, OĤ 3:50). Nevertheless, according to most poskim an incandescent filament has the same status as a flame, and the entire appliance is considered secondary and a basis to the filament and thus completely muktzeh (SSK 20:15*; Minĥat Yitzĥak 3:43; Yalkut Yosef vol. 2, pp. 425-426; Orĥot Shabbat 19:181-184). See Harĥavot.