Professional leather goods repair shops can retouch and refurbish the leather, making it almost as good as new. As far as I know, there is a leather beauty shop in Tianhe District, Guangzhou. It is located in Huajing New Town. It can repair and recolor leather goods, dry cleaning, etc. It can deal with sweat stains that cannot be removed. You can find information about this store by searching for "Guangzhou Tianhe Huajing Leather Beauty" online.