As basic as possible?
Take nothing!
Tooth care - chew the end of a hazel twig until it becomes fibrous and use it as a toothbrush with wood-ash from your fire (or salt) as toothpaste.
Soap/shampoo - wash down with dry sand or water that has had wood-ash soaking in it overnight.
Toilet paper - leaves (Foxglove is my favourite - avoid nettles) or snow or moss or smooth rocks.
A civilised basic kit - small soap or travel soap (for everything from hair to carrots), T paste, t brush, "Magic Chammy" synthetic towel, footpowder, small roll-on deodorant, small comb (if you have hair), enough comfy bum and hand gel sanitizer, bic lighter.
Longer trips, solar shower (drybag type - multi -use item), nail clippers/ small scissors