If you have super bad carpet, stained, holey, Moldy… replace them. Take them out, measure them and go buy some carpet that you like. Trace, cut, and replace. It’s not a hard job, but it is time consuming. If you have minimally problematic carpet, take it to be cleaned. I just bought my 3000 gt and on the whole it has been very well maintained, however, it had old man smell I couldn’t stand it. The carpet and leather looked clean, but I cleaned the leather and carpet anyways, by hand using a moist towel soaked and then wrung out with mild soapy water. As I cleaned it, the water in the bucket turned super dirty even through the leather and carpet looked clean. When I was done, the old man smell was almost gone. I did as Joe mentioned in one of his videos and conditioned the leather with Maguires leather product and boy, that has a very nice new car smell to it! My car interior has been restored! it took a few hours but it was definitely worth it. I did it by hand to minimize risk of water rusting the metal under the carpet.