I have brown stains on the underside of some of my non-stick pans. If you scrub intensely with an abrasive sponge you can get some of it off. Is there anything that will take this off more easily?

My carpet is a few years old. It's never been professionally cleaned. I've used the supermarket rentals and then got a Bissell home machine. Now the Bissell doesn't work any more. I'm a big do-it-yourselfer and I want to invest in a commmercial-type machine so I have a properly cleaned carpet. I could pay professionals to clean the carpet but I'm perfectly willing to and capable of doing the work myself, but I don't know where to start in shopping for the proper tool. And I know a good machine would be expensive, but I'm willing to make the investment. What are the best brands and types of professional/commercial machines?