Does anyone know what this is？
 |
I have cleaned several times. But, it keeps showing up. Is this caused by some kind of insect? If it is, what kind of insecticide I should use? Thank you very much for your help in advance. submitted by /u/CarinaWang88 |
![[link]](https://i.redd.it/4odxirvnn16d1.jpeg){kind=link}