What is the ruling on opening a private veterinary clinic to treat ornamental dogs and cats and earning money from it, and is it permissible to refuse to treat a dog during official working hours, and what are the details of the impurity of dogs for veterinarians and how is it purified?

The saliva, sweat, and waste of a dog are impure, and anything they contaminate must be purified. It is permissible to designate special protective clothing and tools when touching dogs for a legitimate Sharia-compliant reason. It is permissible to keep dogs for guarding (crops, livestock, or against enemies), provided they are kept away from the reach of children. It is forbidden to keep them without a need, such as for adornment, because it diminishes the reward of the keeper and prevents angels from entering their home. It is permissible to treat a dog whose keeping is authorized. However, opening a clinic to treat ornamental dogs is not permissible because it is considered aiding in sin.