1951 D Lincoln Wheat Cent Damage - Likely Acid Bath

This one is getting posted because while I am pretty sure it's just damage, the coin is interesting. It was found in a regular old bag of circulated wheat cents, and wasn't hard to see something going on. Or feel something going on, as it is thin and only weighs 2.57g.

I diagnose this as an acid bath due to the overall reduction in weight without losing too much detail, as well as the thinning of the rims. A quick check puts the diameter at 18.9mm so yes it is too small.

But how those raised lines on both sides ended up there is a mystery. Maybe it was in a cage when it was dunked in acid and those areas just didn't get eaten down along with the rest of the coin. Anyway, just a fun one to ponder over.

1951-D Lincoln Wheat cent damage - likely acid bath