It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) "forbade the earnings of slave-women."
It is possible that what is meant by this prohibition is the slave-woman who is a prostitute, just as it is reported from Sayyiduna Abu Mas'ud al-Ansari (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) forbade the earnings of a prostitute, and from Sayyiduna Rafi' bin Khadij (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "The earnings of a prostitute are foul."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الإجارة / 11687
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) "forbade the earnings from a dog and the earnings of a singing woman."
The Shaykh (may Allah have mercy on him) said: It is possible that he forbade earnings about which it is not known where they earned them from, out of fear of falling into what is unlawful.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الإجارة / 11688
Tariq bin Abd al-Rahman al-Qurashi said: Rifa'ah bin Rafi' (may Allah be pleased with him) came to the gathering of the Ansar and said: Today the Messenger of Allah (peace and blessings be upon him) forbade us certain things; he forbade us "the earnings of a slave-woman except what she earned with her own hand", and he gestured with his finger, like spinning, baking bread and embroidery.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الإجارة / 11689
It is narrated from Sayyiduna Rafi' bin Khadij (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) "forbade the earnings of a slave-woman until it is known where she earned it from."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الإجارة / 11690