Sahih Muslim Bk 30, Number 5761:
rAnas b. Malik reported that Allah's Apostle (may peace be upon him) used to come to our house and there was perspiration upon his body. My mother brought a bottle and began to pour the sweat in that. When Allah's Apostle (may peace be upon him) got up he said: Umm Sulaini, what is this that you are doing? Thereupon she said: That is your sweat which we mix in our perfume and it becomes the most fragrant perfume.