
Cornstarch and baking soda are easily found in the grocery store and make good substitutes. They also recommend tapioca starch, arrowroot powder, Kaolin clay, rice starch, and oat flour. See the complete list in this article:
Michelle Llamas, March 30, 2021. 7 Alternatives to Talcum Powder that Don't Cause Cancer. https://www.drugwatch.com/news/2018/06/25/7-alternatives-to-talcum-powder-that-dont-cause-cancer/
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