852. Terumah on Shabbos
Shabbos 25:20
A Yisroel (i.e., a non-kohein) is permitted to carry terumah even though he may not eat it. One may carry terumah that has been rendered ritual unclean together with terumah that is ritually clean or with regular produce as long as both types of produce are in the same vessel. This only applies when the ritually-clean terumah is on the bottom and the terumah is a type of produce that would be ruined by being spilled on the ground. However, if the produce is something like nuts, one must spill out the contents of the vessel and take the permitted produce, leaving the prohibited produce behind. If one needs the spot where this vessel is resting, he may take all the produce at once regardless of whether the ritually-clean terumah is on the top or the bottom.
Shabbos 25:21
Let's say that a person intends before Shabbos to use a row of stones on Shabbos. If he prepares them, he may sit on them on Shabbos, otherwise he may not. If a person gathers branches for use as fuel but he changes his mind before Shabbos and decides to sit on them instead, they may be carried on Shabbos. Certainly, if he actually sat upon the branches before Shabbos, is permissible to carry them.