850. Muktzeh Items on Top of Non-Muktzeh Items
Shabbos 25:16
A person may pick up his child on demand even if the child is holding a rock but not if he is holding a coin. This is out of concern that the coin may fall and the parent will come to pick it up and carry it. If a basket has a hole and a rock has been used to plug the hole, the basket may be carried. This is because the rock has now become part of its structure. If a basket is filled with fruit with a rock among them, the following rules apply: If the fruit is soft like grapes or berries, the basket may simply be carried. This is because spilling the fruit out of the basket would ruin it and the Sages did not institute this enactment in an instance where one would incur a financial loss.
Shabbos 25:17
If a person forgets and leaves a rock on the opening of a barrel, he may tilt the barrel to make the rock fall off. If the barrel in question is among other barrels, it should be moved elsewhere and then tilted. Similarly, if one forgot and left money on a pillow that he needs, he may shake the pillow to make the money fall off. If he needs the spot where the pillow is resting, he may move the pillow even though there is money on it. However, if one intentionally put money on a pillow on Friday, or put a rock on the opening of a barrel, these items may no longer be moved on Shabbos even if the muktzeh item is removed. This is because utensil has been rendered a base for the muktzeh.