✔ 最佳答案
i can teach you very easy.you can buy the cleaner from the supermarket,i always use it for my dirty on my shirt especially the white shirt.you spray it on the surface and use the teeth brush and water to clean it ,ok.the good cleaner brand is "kiwi" its about $15 to 20 .cheap.because you long champ is expensive. \
do it now.hope i can help .bye.