943. Using the Succah Decorations, et al.

134:12 We are forbidden to benefit from the wood of the succah - both of the walls and of the schach -  until after Simchas Torah, because they were designated for fulfilling the mitzvah. (This refers to types of benefit that nullify its use and not to such benefits as leaning on it - Mishnah Brurah 638:4.) It is prohibited even to take a splinter for use as a toothpick. All this remains true even if they fell down, and stipulating a condition to the contrary is of no effect. If Simchas Torah fell on a Friday, the wood remains prohibited through Shabbos. The decorations of the succah are also prohibited to benefit from, even if they fell down. Since they are prohibited for use, they may not be handled on Shabbos and yom tov because they are muktzeh. One is permitted to smell an esrog that was hung in the succah as a decoration because it was not put aside to preclude smelling it.

The practice is to prohibit the use of decorations that were hung from the schach even if one made a condition to permit them but one may use the decorations that were hung from the walls if such a condition was made.  One may remove paintings that were hung in the succah for decoration so that they won't be ruined by the rain. Even if no overt condition was made, the assumption is that they were hung with this intention. (Since there is an implicit condition, the paintings may be moved for any reason, not just because of the rain - Shaar HaTziyon 638:26.) In any event, it is preferable to make an explicit condition at the outset, specifically before twilight on the first night of Succos. To do this, one stands in the succah and says, "I make a condition that it will be permitted to eat and to make use of the decorations of this succah whenever I so desire." One must be careful that succah decorations that he intends to remove on yom tov are not tied with a knot that is impermissible to untie on a Festival.

134:13 After yom tov, when removing the schach, one must not step on the branches or use them for a disgraceful purpose. This is because they are objects of a mitzvah, like tzitzis.