These flowing hair coins are exceedingly rare. They were replaced with draped bust coinage, which look similar, in 1795.
If you think you have a genuine specimen, by all means contact a knowledgeable collector or professional coin dealer for an in-person inspection.
NEVER CLEAN A COIN. CLEANING RUINS VALUE.
Very approximately, catalog values in US dollars are:
HALF DIME: 16 mm diameter, $800 heavily worn, $8000 well preserved
HALF DOLLAR: 32 mm diameter, $800 heavily worn, $10000 well preserved
DOLLAR: 40 mm diameter, $1600 heavily worn, $16000 well preserved
As with all valuable coins, fakes are possible. Our graphic to the right shows four fakes, and many other fakes exist. When a replica coin shows the word COPY somewhere on the surface, it is a legal reproduction, and legal reproductions are bought and sold as collector items for a few dollars or tens of dollars. Most fakes are meant to deceive collectors. These are the illegal ones.