If I owned the coin, I’d leave it in the holder, place it in an auction at no reserve (and possibly a conservative minimum opening bid) and hope for the best. If you list it on EBay, you could note in the description that you bought it from a reputable seller as a problem-free example.
if you check auction archives, you should be able to find results for AU details, cleaned examples of that and/or other dates of similar value.
I realize that yours is a Curl Base 2, but here are two sales of Square Base 2 examples, from this year:
Auction 132043 | Lot 25787 » Half Dollars » Bust Half Dollars
1828 50C Square Base 2, Small 8s, Large Letters, -- Cleaning -- PCGS Genuine. AU Details. From The Maltese Collectio...(PCGS# 6151)
Bid Source: HA.com/Live
SERVICEPCGS Genuine
GRADEAU50
AUCTION ENDED
Oct 20, 2020
Auction Archives
Sold For: $192.00
Auction 132026 | Lot 27157 » Half Dollars » Bust Half Dollars
1828 50C Square Base 2, Small 8s, Large Letters, -- Cleaning -- PCGS Genuine. AU Details. ...(PCGS# 6151)
Bid Source: Internet
SERVICEPCGS Genuine
GRADEAU50
AUCTION ENDED
Jun 23, 2020
Auction Archives
Sold For: $312.00