May decorations that were manufactured for the gentile holidays [i.e. Christmas] be used for a Sukkah?[1]
Yes. The decorations do not become prohibited in use unless they are purchased second hand after being used by the church and the like. Their simple manufacturing does not prohibit them. Thus, one may purchase bulbs and lights for one’s Sukkah from a store even if it is also purchased for the gentile holiday decorations. Nonetheless, one should not use decorations that are distinct in use for the gentile holidays in areas that those gentiles are found.[2]
[1] Shevet Halevi 2:57 based on Temurah 29a, Chasam Sofer O.C. 42; See regarding Hazmanah Lav Milsa Hi: Admur 42:4 and 6; Michaber 42:1; Brachos 23b; Sanhedrin 48a; Mordechai Megilah 819; Nimukei Yosef Sanhedrin end of chapter 6; See regarding not using ornaments of idolatry: Michaber Y.D. 139:13; O.C. 154:11
[2] See M”B 494:10 in name of Gr”a and Chayeh Adam, that the custom of placing plants and trees in shuls and homes on Shavuos was abolished due to it being similar to the gentiles, referring to the Christian festivals.