You checked two and a half of my four boxes for an ideal Buff
with this one:
an early die state obverse and reverse, with a matching die state pairing (notice the date and central feather details on the obverse and the legends on the reverse)
no excessive die polishing to eliminate a clash
half a check for the strike, which is pretty decent for 1914-S
The strike looks soft on the obverse, but the weakness on LIBERTY is not a strike issue. LIBERTY was weak on the hubs for 1913-14-15 Buffs. This is a design issue that was corrected in 1916.
The coin is mid-grade by circulation, rather than higher grade. the only box missing.
In terms of grade, start with the obverse and ignore LIBERTY, because it is a design issue. The Indian's hair is distinct from the forehead and cheek. The braid shows separation and some detail. Both ribbons are distinct, strong, and complete. On the second feather, the rachis and calamus are clear and complete. The date is full and strong. The obverse grades VF-30.
The reverse is more mixed. There is 1/4 of the hair on the buffalo's head, and 1/2 of the hair on the back. The tail is complete, but not split. There is some detail on the front shoulder and lower front left leg. The eye and beard have decent details. Both rear legs show some detail. Legends are intact and distinct from the rims, and the head and tail (barely) are separate from the rims. With the sole exception of the horn (only 2/3), the reverse is VF-30.
Even if the reverse is knocked a step to VF-25 because of the buffalo's horn, this coin still nets to VF-30, and would command some premium for the early die state.
The surface crud doesn't bother me. If you do the acetone thing, letting the buff do the backstroke for an hour or so would loosen the crud and leave a more eye appealing surface. I don't see anything here that would detail the coin.
Frankly, I'd jump on this coin, too. EDS 1914-S Buffs are scarce as hens' teeth. At $36, you came in below where I would expect to see this one trade. I think it would go north of $50. Well done!