Hi! There are certain items which, if necessary, are permissable for use on Shabbat but that would otherwise be muktzeh....such as scissors. However, people do not usually designate these items as "Shabbos items" before Shabbat starts. Why is it that certain items such as "fancy dishes" have to be designated before Shabbat, while others (such as the scissors) can simply be used "if needed". Thanks!
Shalom, Thank you for your questions. The laws of mukzah are some the most involved of the Shabbat laws, and require much in depth study in order to grasp them in their entirety. So, with that in mind, let me try to give you a quick start to understanding mukzah. Things which are utensils (as opposed to sticks, stones, sand etc), but whose major use is for something that is forbidden on Shabbat (such as a pen, or scissors) are called "kli sh'malachto l'issur". The rule that regulates their use is that they are mukzah and cannot be moved, unless it is moved either 1)to use the place it is resting on, or 2)to use it for a permitted Shabbat use (like a hammer to open nuts). Based on this you will understand the answer to your query about the scissors. I am not sure where you learnt that "fancy dishes" have to be designated before Shabbat – in fact the law is that dishes (no matter how fancy) are vessels that are marked as for a permitted use on Shabbat and as such may be moved for any purpose at all. There is a category of called "machmat chrisron kis" that includes precious items that are generally not moved at all, such as a surgeon's knife, and they are considered totally mukzah on Shabbat and cannot be moved for any reason (as opposed to the type of mukzah we saw above). Perhaps you are referring to those type of objects? (If you wish to send me the source for what you wrote I'd be happy to try an explain it). Blessings.