When sourcing used jute sacks, the primary focus should be on structural integrity and cleanliness. Buyers must verify the grade of the sack (e.g., Grade A for food-grade reuse or Grade B for industrial use). Key technical specs include fabric weight (typically 600g to 1000g per bag), dimensions (standard 26"x44" or 28"x40"), and weaving density. Ensure the sacks are free from large holes, rot, or excessive oil stains, as these factors significantly impact the load-bearing capacity and suitability for agricultural storage.