How do you remove these?

[moretacos]

I think it's called a push nut washer or Starlock washer?
Anyhow it's in the rear wheel wells behind the tire. There are no threads, and it is kind of thin and dont know of any tools that can be used for this. Help?

 

[Eto Demerzel]

they are one use locking washers. the teeth dig into plastic nub.
Usually a flathead or trim pry tool will pop it off without breaking the nub.
Use a pick to bend back the teeth off the nub if you can- if you don't have a new washer, hammer the old one flat and push it on when you're done.