What to do with the Riester?

I had a Riester contract talked into me 15 years ago. That was probably a good thing because otherwise I would have spent the money. Know my then-self. In the last few months I have started to think more about my finances. Saving now runs on different levels and is 100% under my control. Well, what do I do with the old Riester? I was a low earner or non-earner 90% of the time with correspondingly small contributions, I contributed c