1. Cocoa is tenacious, smeary powder and hard to get out of the container when you get to the dregs. The best way to do it? Add a big spoonful of granulated sugar, put the top back on, and shake vigorously, letting the sugar rub away at the cocoa. Dump the (now brown) sugar out, and repeat again as necessary, using the cocoa-ed sugar to make (for instance) cocoa!
2. This is what you need to clean your computer keyboard: STIM-U-DENTS. Trust me. They are genius.
They are made from squishy balsa wood, with an elongated triangular point, which makes them ideal for attacking the between-key spaces from many angles and for buffing away layers of grime. They are cheap, so you can use as many of them as necessary. And the wood is absorbent, which allows them to attract hairs and crumbs. They are a great thing to have near your computer for when you're staring out the window or something and can idly clean away.