Wash them clothes....how?

[The Local Ned]

What you use , ideally , should be dictated by the circumstances.

If you are in your final BOP then it should have some form of water able to be used in it.
This carries little risk in itself.

If you are in the 'field' so to speak and are moving around then I would be very , very cautious regarding washing clothes and self. You are very vulnerable near water , we all know animals need water to survive ,they may use the area you are near , it may even have some form of edible fish swimming around in it.
These make the water course an ideal position for foragers to keep under observation - if they see you washing your clothes etc ,then not only is your security compromised , your safety may well be too.

If clothes are to be washed then choose a site that you can easily bug out from and straight into some form of cover.
Have sentries out.

As for hygiene - same rules apply - in the field - bag it/seal it and bury it if possible....dogs will sometimes struggle to pick up a scent from old waste , especially when sealed and buried properly.
When using TP - remember - it burns , and can be disposed of this way.

In the BOP then personal hygiene will likely be more of a priority than security / remaining undetected.
I know of no natural substitute for TP , large 'dock' leaves have been used in the past , not ideal , but they do the job.