I bought someone’s stamp collection from the goodwill store for a couple of dollars. One stamp that caught my eye was a 1923 rotary press perforated 2 cent George Washington used postage stamp in red ink, and found on the hobbizine website that it could be worth $300.00,and there is a lot of commemorative stamps in the collection worth like 20 cents a peice. They also smell a little like mildew, but are not damaged from it. My question is are they worth anything being in that condition?