Yep baby wipes without perfumes, and for more sticky things I use a soft makeup sponge. For detail I use extra cotton earwax sticks. I always dry with normal cotton or an usb fan and my soft cotton gloves which serves two fold. No fatty fingers and automatically drying effect.
For light I use a pro head mounted lamp. You see dirt much better. I also use this kit when I visit house holds for loose figure inspection (and magnifying glass)
I never bathe them. And oh yeah my dolls are looked after. I still don’t have a clue how to display all 600 though so I might end up selling a “complete” 110 ish batch with the most common variations... here on this site of course first.