Muhaysa asked the Prophet ﷺ about the earnings of a cupper he owned, and the Prophet ﷺ forbade him from it. He kept pressing the matter until the Prophet ﷺ said, "Use it as feed for your camel and as food for your slaves."
حدثنا سفيان عن الزهري
أن محيصة سأل النبي ﷺ عن كسب حجام له فنهاه عنه فلم يزل به يكلمه حتى قال اعلفه ناضحك وأطعمه رقيقك