One of the categories of Muktzeh – objects forbidden to be moved on Shabbat – is that of "Keli She'melachto Le'issur," or utensils whose primary function is forbidden on Shabbat. A pen, for example, is used primarily for writing, which is included among the thirty-nine areas of forbidden activity on Shabbat. Although pens can also be used for scratching one's back or prying open a lock, since they are used primarily for writing they are classified as a "Keli She'melachto Le'issur" and may be moved on Shabbat only under certain conditions. Likewise, a telephone, whose primary use is forbidden on Shabbat, falls under this category and is thus deemed Muktzeh. By the same token, a pot is used primarily for cooking, one of the activities forbidden on Shabbat, and may therefore not be moved. If a pot contains food, then it may be moved because of the permissible status of the food. (Menuhat Ahava, Helek 1, Page 260-261)
All these objects are Muktzeh even before they have been used, since they are designated primarily for activities that are forbidden on Shabbat. (Ibid, page 262)
What would be the status of an empty wallet? A wallet containing money would obviously be considered Muktzeh because of the money; but would an empty wallet have the status of Muktzeh?
The authorities distinguish in this regard between a wallet that had already been used for money, and a new wallet that one has yet to begin using. Some people use wallets for permissible items, such as papers, pictures and the like. Therefore, a new wallet does not yet have the status of Muktzeh, and it may be moved on Shabbat until a person begins using it to hold money. Once he stores money in the wallet, he determines its primary function as holding money, and the wallet thus becomes Muktzeh and retains that status even if it happens to be empty. But if a person had never used the wallet, it is not Muktzeh and may be moved on Shabbat. (Ibid, page 262)
This would apply as well to other objects that do not have a single, primary function. For example, some glass holders can be used for either drinking or as candleholders. Such a holder may be moved on Shabbat until a person begins using it for candles. Once it is used for a candle, it remains forbidden even when it does not contain a candle.
Summary: Objects used primarily for an activity forbidden on Shabbat, such as pens, telephones and pots, are deemed Muktzeh and may be moved only under certain conditions. Pots containing food, however, may be moved on Shabbat. An empty wallet that has never been used to contain money is not considered Muktzeh; if a wallet has been used for money, one may not move it on Shabbat even if it is presently empty. Similarly, a glass holder that can be used either for drinking or to hold candles does not become Muktzeh until one uses it for candles; once it is used for candles, it may not be moved even when it does not contain a candle.