1791 Columbia 8 Escudo Nuevo Reino Grade Help

AU details

Those "scratches" may or not be adjustment marks with some grime in them - hard to tell due to the overall strange surface (see below). Though naturally occurring (as made), aesthetically, they sort of have the same effect. PCGS/NGC often WILL straight grade such pieces... though they will never grade strongly within the UNC range - and may even get netted down a bit as high circs.

The bigger issue is that the planchet seems to have suffered from some improper annealing or alloy mixing issue on much of the obverse. Almost looks at first glance like "sweating" (what happens to the surface of gold after heavy jewelry use, or getting banged around a lot in bags, etc.), but probably can't be that as it's isolated to only a portion of the coin, and obverse only... unless it was in some strange uneven setting that exposed only that portion (which I doubt).

Almost tempted to say some substance did that to the surface (and NOT salt water, which wouldn't come close to doing that)... but as gold only really reacts to a few acids in that manner (and if you know what they are, you wouldn't expose gold that much to them!)... I assume it was something in planchet prep.