Stamp trader Wang Chung-jih points out that stamps are only considered in excellent quality if they have not yellowed, not mildewed, not faded, not been soiled, have no rip marks, and have preserved the stickum on the back and the tooth-edged border in their totality.
郵社業者王中日指出，郵票要不發黃、不發霉、背膠完好、齒孔完整不缺角、沒有汙損、不褪色，沒有折痕，才夠得上品相佳。