How do you wash her, standard dish soap or is there something particular you find works best?
Is it a TPE doll you're getting?
How you clean them is different for TPE or silicone.
Personally, I don't wash my dolls. Like for 5 years I haven't washed them, except the odd one or two. If your doll got really dirty, you can wash them, but if they don't look dirty, just leave them be. The more you wash them, the quicker you wear them out.
TPE dolls, generally use Johnsons baby bath (mild soap), dry them off, then Johnsons baby oil and wait for the oil to be absorbed (oil does nothing for some TPE brands), finally a good powdering and gently brush the powder off.
Silicone dolls, the same but
don't oil them (oil is bad for silicone.)
Simple.
And if you like to cream 🥧 your doll. Cleaning is simple too. Stick your fist in (if it's a TPE doll, they are very stretchy - silicone dolls, probably not a good idea) and grab as much jizz as you can with your hand. Then with some quality kitchen roll from your local supermarket (I use Plenty), stuff that inside her, wiggling it around, in and out, until the towel comes out feeling quite dry. Then stick an aquarium pump up her for a few hours and she'll be as dry as can be (it's moisture which is a problem, leave any moisture inside her and she'll go mouldy).
As someone who has been cream 🥧 ing my dolls for years (my favourite sex doll is 5 years old), and I'm still alive, I know it works.