Cleaning iron/ scale deposits using glass bead for Nigel on water meter parts

This Video is for Nigel
He needed to clean the iron/scale based deposits off surfaces as shown in the video.
These parts are from water meters used mostly in the agricultural sector that collects water borne deposits over a number of years. They have to clean those deposits off to get back to the original material during the servicing of the meters.
I think the glass bead did that lovely