I agree that ONR is the best for maintenance detailing. BUT when you are trying to detail a disgusting mini-van that has been hauling around children with sticky fingers, ONR isn't necessarily sufficient. Which is why I HIGHLY recommend Einszett 1z Blitz APC. I dilute it 1:30 for leather, vinyl, rubber trim, plastics, seat belts, etc. I also keep a bottle diluted 1:100 for carpet cleaning. It is completely safe and will not dry your hands out or cause any sort of skin irritation like the other popular APC's and Degreasers. Naturally, it isn't going to preforms as well as products like Optimum Power clean for heavy duty exterior cleaning. But it is safe for all surfaces on the interior and because it doesn't leave a residue I have effectively used it as a glass cleaner for windows with sticky finger prints/dog slobber.
Also, if you aren't convinced. I also pour 1oz. of Blitz into the 5 gallon bucket I pre-soak my polishing pads in and just 1oz. will remove 90% of the compound/polish residue. I have even started pouring 1 ounce into the washing maching with my microfibers instead of OPC.
By the way, Blackfire's interior cleaner is another product that is so safe and gentle I would almost feel comfortable washing my hands with it, but it's price point is targeted more towards the Enthusiast rather than the professional detailer. Just another option. Hope this helps!!