I've never heard of an actual formula for valuation, but you can try comparing closed Heritage auction prices. If you can't find an "improperly cleaned" XF40 example you can something similar. For example, under Seated halves do a search "improperly cleaned XF40" and the see how those prices compare to problem free examples. Hunt around and you can probably a establish a price reduction range on a percentage basis.
My personal preference - just get a lower grade problem free example. I'd rather have a coin with a bit more wear and no disclaimer.
My personal preference - just get a lower grade problem free example. I'd rather have a coin with a bit more wear and no disclaimer.




















