I basically use a sharp scribe to do as you do, but add just a tiny little flip upwards as I remove the point to remove a tiny bit of the metal. As i go along I will scrape a fingernail over the work to remove burrs.
Great work...especially the eyes!
There was an engraver who came to the Vegas shows several times who had the problem of acidic hands. As I remember it, there is a soap that can help with the problem but I do not remember anything else about it.
Just a thought...acidic oil from hands can cause a problem like yours. I engrave on a steel gun part sometimes for months without any rust problem. Even when I lived on Kodiak Island which is a very salty air location.
A small correction for John B. The Engraver is a quarterly publication, not a monthly one. Wish it was monthly but it is a huge amount of work for the editor as is!
That is steep for soft metal which I seldom cut. I do use 45 degrees on aluminum which I have used for guitar/uke inlays and some car parts. The vast majority of my cutting is on gun steel.
I use a 90 degree carbide tool for all my scroll cutting and most everything else. My depth of cut for most work is in the range of .003 to .005" with sculpted work going to maybe .015". It all depends on the design needs...something you will develop with experience. I use a face angle of 57...