The black residue on the cat is caused by fleas. You can put the black residue on a paper towel and drip it with water to check to see if the black residue turns red. If it turns red, it means the cat needs to be dewormed, and it should be dewormed regularly every three months. If it doesn’t turn red, it’s cat moss.

How to get rid of fleas on cats:

1. Wash your cat more often, especially in summer, be sure to bathe it more often. Itching is generally not contagious. Just pay attention to your cat's hygiene and you'll be fine.

2. When raising a cat, everyone must pay attention to the cat’s nails, which are particularly easy to scratch people. Therefore, if your cat’s nails are too sharp, you can trim them appropriately.