anything that evokes nostalgia and will never be made again . . .
I collect glass perfume bottles/presentations. Much of my collection is from 1920-30, some earlier,none after about 1955, all by noted glass artists, historically evocative brands, emphasis on the figural. I bought them carefully over 40 years. I limited myself to paying no more than 1/3 of *book*. In 2007, my collection was worth more than 2x what I had paid for it. Since 2008, it is worth about half, IF a buyer existed.
I see wonderful, rare, pristine, historically important pieces up for sale on eBay for 1/3 of their value and the pieces do not sell. It is a fantastic time to buy, of course, but fewer collectors have the extra money and they are savvy enough to wait until the seller is desperate.
These are real, irreplaceable antiques made by recognized masters and many are historical cultural icons, not manufactured *collectibles*.
However, a dedicated website I follow seems to have a better track record and is realizing prices which are closer to real value. That might be the best way to sell, rather than eBay, given good keywords and search engine visibility.
My husband inherited a set of Copenhagen plates from his mother. Next to worthless, from what I can tell.
Hussein squats in our WH and everything goes bust. When people don't have money, collections become worthless. IF the economy every turns around, prices might go back up.