So there’s Memorial Day weekend BBQ in your Canon EF 50mm f/1.8 II lens and it’s ruined—shit happens! But instead of crying or buying another lens, you might take a stab at this disassembly guide for a (careful) fix.
While the guide does come with its fair share of warnings and steps, it is completely doable, as Boing Boing’s Rob Beschizza discovered when he used the guide to smooth out the focus mechanism and repair his lens’s autofocus. He also deviated off the beaten path a bit with some superglue, although you should definitely review the guide first, proceed at your own risk and apply any and all glue sparingly and with a steady hand.
Also, be more careful next time! [Yosuke Bando’s Lens Disassembly Guide via Beschizza]