I remember I used to mine (by solving captcha's) this coin back in the day when it was called Raiblocks.
It was actually not worth it at all because what people were paying for XRB back then worked out to maybe $1/hour or so.
I used to do it mostly out of boredom, forgot about it completely and then when it turned into Nano, I remember I might of had some left in my old wallet, and low and behold it was there.
So I kind of got lucky with this coin since I haven't sold it earlier, but it was pure luck. Pretty much no different than people mining BTC in 2009 and forgetting about it for 5 years or so and then remembering that they had a wallet.dat file somewhere.
I wish you remembered about it in December. You would be pretty surprised and much more lucky

) However I'm still holding a part of mine. I like the tech side of the project and its team.