I use the Bissell Little Green solution 5:1, then scrub and extract with hot water in the Little Green on carpet/mats. Works great for me. Woolite foams up A LOT unless you dilute it A LOT, so you might want to avoid that on carpets if using an extractor like a Little Green. I use Woolite 6:1 on plastic interior, and leather to clean. I just bought Quick Interior Detailer after reading so many good things about it on here, and I like it. I use Simple Green 5:1 on wheel wells, but honestly it's so much easier to just spray them down with Armor All tire foam, but not NEARLY as cost effective. I just hate scrubbing wheel wells, takes forever and sometimes doesn't give me the results I want.