Ask HN: What to do with my old product?

So I have a product, its actually a twitter client for firefox, that has been around since 2007. I no longer want to support it (never was able to monetize it). So my question is, what is the best way to A: monetize a firefox plugin (inline banners never worked, no context to run ads against, no one clicked ever), and B: where should I sell it off? It has 15k daily active users and about 50k current installs.

Is flippa a good place to unload this?