1. Look: Sponge craftsmanship is mainly divided into two categories: foaming and PU. Doping makes the fake sponge foam unevenly and has large holes. The pure sponge has small and even holes;
2. Touch: Pure sponge feels fine and smooth, doping makes fake sponge feel rough and has poor elasticity;
3. Squeeze: It seems that the sponge of the same thickness and hardness is mixed, so that the fake sponge is prone to dent once it is squeezed, and it will not spring up after sitting down for a long time; the pure sponge has strong support and it is difficult to deform after long-term extrusion;
4. Price: Doping makes fake sponges greatly reduce the cost and low price due to the addition of stone powder; polyurethane materials used in pure sponges are more expensive than adulterated sponges;
5. Lifespan: Adulterated sponges are prone to slipping due to the addition of stone powder and hand-picked; pure sponges are durable;
6. Comparison of tensile strength between adulterated sponge and pure sponge: For sponges with the same appearance, the longer the stretch, the better the tensile strength;
7. Comparison of fracture strength between adulterated sponge and pure sponge: For sponges with the same appearance, pure sponges can bear a strong load.