Monitor yoke

Originally Posted by toula

Ferrite.

Throw it in your steel bucket, it's powdered iron/? From Wiki;

Ferrites are chemical compounds consisting of ceramic materials with iron(III) oxide (Fe2O3) as their principal component.[1] Many of them are magnetic materials and they are used to make permanent magnets, ferrite cores for transformers, and in various other applications.

You didn't forget the "silver" wire that ran around the bottom edge of the tube, did you?? It's tinned copper.