PP/HDPE (polypropylene/high-density polyethylene) are well-suited for weak acids, weak alkalis, fertilizers, water-based paints, and cleaning agents. However, strong oxidizing agents, highly concentrated strong acids, and certain potent solvents (such as some aromatic hydrocarbons) can corrode the plastic. Always conduct a small-scale immersion test before use. For hazardous chemicals, ensure you use plastic drums that carry the appropriate certification for the transport of dangerous goods.