Look at MIT and UC Berkeley’s CS curricula and start tackling things that you haven’t covered. They’re both available freely online and you might still be able to find video recordings of Cal’s lectures somewhere (they recorded every class for students who weren’t present or had difficulty understanding in real time until 2015 or so but were hit with an ADA accessibility lawsuit because they weren’t captioned or something.)
Honestly? I just fill the remaining weight in the grinder with whatever I’ve opened to brew next. Unless the old beans are getting stale, then I just bin the tiny remaining amount.