Plain, raw, unprocessed, and unflavored whole almonds that contain zero added ingredients, oils, preservatives, or flavorings generally do not require a formal hechsher (kosher certification) for Passover or year-round use, provided they have not been processed on shared industrial equipment handling non-kosher items. However, shelled, slivered, blanched, or roasted almonds, as well as those packaged in commercial facilities utilizing shared lines, frequently require reliable kosher certification to ensure they are free from insect infestation and prohibited contact.