When evaluating glycerine soap, the glycerine content is paramount; high-quality transparent soaps typically contain 10% to 15% added glycerine to ensure humectant properties. You must verify the TFM (Total Fatty Matter) content, which should ideally be between 40% and 60% for transparent bars to balance cleansing with mildness. Additionally, check the pH level, which should be maintained between 8.0 and 9.5 to ensure it is skin-friendly while remaining an effective cleanser. For transparency, ensure the supplier uses high-purity polyols rather than excessive alcohol, which can dry out the skin.