The status of kelim used for both permissible and forbidden activities is determined by the majority of their use (Pri Megadim; MB 308:10). Therefore, a pocket knife with scissors is not muktzeh, because most of its blades can be used as cutlery for eating and are not muktzeh, and it is only the scissors that are used primarily for a forbidden activity. Similarly, a wristwatch with a built-in calculator is not muktzeh, because its primary use – telling time – is permitted on Shabbat. In contrast, a cell phone (that is not a smart phone) that displays the time is a keli she-melakhto le-isur, since its main use – as a telephone – is prohibited on Shabbat. Therefore, it may not be moved for its own sake, but it may be moved le-tzorekh gufo – in order to see what time it is (however, he should not carry it around in his pocket for that purpose). It may also be moved le-tzorekh mekomo. Thus, if one wants to use the place where the phone is resting, it may be moved. Similarly, if the phone’s alarm goes off, and the owner wants to move it so the ringing will not disturb his rest, he may do so.
A pot is a kli she-melakhto le-isur, since its primary purpose is for cooking. Nevertheless, when there is food in it, the pot is secondary to the food, and therefore may be moved. Once the food has been removed from the pot, one may remove the pot from the table, even if one does not need the space it is occupying. The reason is that the food waste at the bottom of the pot renders it disgusting, and a disgusting item (graf shel re’i) may be moved (MB 308:20; BHL s.v. “kli”; see section 12 below).
Even if an oven is used to store baking pans and baked goods, since its primary purpose is baking, it is a kli she-melakhto le-isur. Nevertheless, one may open its door to remove food, since this is moving it le-tzorekh mekomo. If one wishes to put food in the oven and keep it there on Shabbat, he may open the door and close it, because this is le-tzorekh gufo (SSK 20:79).
Tefilin are considered a kli she-melakhto le-isur, since one may not wear them on Shabbat and Yom Tov (SA 31:1). Therefore, they may be moved only le-tzorekh gufam or le-tzorekh mekomam. Le-tzorekh gufam would apply if one wishes to put the tefilin on, in the hope that they will protect him from danger. Le-tzorekh mekomam would apply if they are sitting in their bag together with a talit, and one wishes to remove the tefilin in order to get to the talit on Shabbat (Taz; MA). Under pressing circumstances, if the tefilin are in danger of being damaged, they may be moved (MB 31:2; BHL ad loc.).
A flower pot is a kli she-melakhto le-isur, since it is associated with several melakhot – planting, watering, and picking. Thus, it may be moved le-tzorekh gufo – to decorate the table – or le-tzorekh mekomo – to use the place where the flower pot is sitting (see above 19:10).