Matte keg finish

[Tombo]

Hi, a couple of my kegs have developed shiny spots where they have rubbed against each other or something. Is there an easy way to get them back to a matte finish again please? I've tried scourers and abrasive cleaners but they are just making the shiny parts bigger and shinier.
Thanks

 

[MashBag]

Good question.

Google "acid etching stainless Steel"

But its going to be a tuff job. Built in obsolescence?

Stainless fabricators that a electric brush thingy what might do it.