If your pot is stainless steel, I highly recommend Barkeeper's Friend - it's a powdered cleaner, walmart sells it, and it's dirt cheap. It's absolutely amazing on stainless. Oxiclean does a great job of removing crud (and if there's a significant amount of crud, by all means, start with oxiclean), but for that stubborn wort residue on the bottom, BKF gets stainless steel all the way back to that shiny-brand-new look.
If it's aluminum, I'm not certain if BKF is okay or not. There is some info here:
If you DO use it on aluminum I'd highly recommend that no matter what, you boil some plain water in it for a while after to rebuild the protective oxide layer just in case you manage to scrub it off.