Darryl’s Analysis

You have a pretty severe thrips infestation.  Unfortunately you will never be able to kill all of them in one cleaning session.  You must continually kill the new generations because the eggs are essentially hidden inside the plant tissues, impervious to sprays or physical removal (unless you remove the entire leaf).

Here’s what you can do:

• Every few days: use a lint roller to pick up any visible larvae (the little yellow bugs)
• Every week: spray the entire plant with insecticidal soap

Once again, I must stress that getting rid of them will be a gradual and LONG process.  I’m still fighting a small thrips infestation on a few of my most beloved plants after more than a year.  Here are some more pictures and resources: https://www.houseplantjournal.com/thrips/

Good luck!