How to distinguish the quality of wall coating?

Wall covering must first smell if there is any smell. If the coating is not good, there will be a pungent smell and harmful substances will exceed the standard. Feel it with your hands, and you will feel soft and comfortable. You can also cut a sample of wall covering, draw a few strokes on the paper with a pencil and use an eraser. The feeling of rubbing is high-quality wall covering, inferior wall covering is easy to scratch or unclean wall covering.