1973-D LMC Die Damage Or PMD?

I have seen this before on a 1973-d I have and I looked it up and seen a thread on lcr on same type of coin also but that one had black tone.

in 1973 the price of copper raised very high and they experimented with new alloys.

Did you try to weight it to see if it a off mixture of alloys.

Kind of far out there idea, but it was the year they did do a bunch of stuff not just the aluminum.

In late 1973, the price of copper on world markets rose to a point where the metallic value of the cent was almost equal to its face value. The U.S. Mint, which produces billions of cents annually, was faced with a potentially catastrophic operating deficit, due to issues of seigniorage. As a result, the Mint tested alternate metals, including aluminum and bronze-clad steel.

First and second thought was possible acid etching or Die Deterioration. May explain columns though not seen them with this particular effect before.

My eyes keep getting drawn to the lines across the fields, bust and devices. Looks like brush stroke(s). Do they appear to be part of the strike, or did someone give it a coat of clear lacquer or polyurethane? Thanks, Doug.

Edit: Clear Finger nail polish?

It is not coated with anything,did an acetone dip.The lines might be from a wire brush,PMD or abrasion lines,MINT? The extra looking columns?
John1