Certain restrictions apply on Shabbat regarding the objects that one may move. For example, as is well-known, one may not pick up a cellular phone or money on Shabbat, even if he does not plan on using it.
There are, however, several exceptions to this Halacha, including a provision called "Tiltul Be’gufo" – moving an object with a part of the body other than the hands. The Gemara in Masechet Shabbat (154) speaks of a case of a Mukse item situated on an animal, and allows one to push the object off the animal’s body with his head. The Ramban (Rabbi Moshe Nahmanides, Spain, 1194-1270) explains that this is allowed because one moves the Mukse item in an unusual fashion – with his head, instead of with his hands.
This Halacha is very relevant to the not-too-uncommon case of somebody who discovers money on the floor in his home on Shabbat. It sometimes happens that some money falls from one’s pocket onto the floor before Shabbat, and he does not see the money on the floor until after Shabbat began. Of course, it is forbidden to pick up the money on Shabbat. It is permissible, however, to kick the money with one’s foot to a secure place where it will remain safely until after Shabbat. Since this is done with his feet, and not with his hand, it does not violate the prohibition of Mukse on Shabbat.
It should be noted that this Halacha of "Tiltul Be’gufo" applies only when there is a need to move the item in question. One cannot, for example, clean his garage on Shabbat by moving Mukse items without his hands. We refer here only to situations such as money found on the floor, where there is an important need to move the Mukse item.
Summary: When necessary, one may move a Mukse item on Shabbat with a part of the body other than his hands. Thus, for example, if one sees on Shabbat that money had fallen onto the floor, he may kick it to a safe place.