Sugar soap needed?

[Gossamer]

Morning,
I’m about to decorate a room.
Non smoker, a few marks and spills but will get a through sanding as a fair bit of filling needed.
Should I sugar soap the walls or will the sanding take care of any dirt etc?
Thanks.

 

[opps]

I routinely sand walls prior to painting them. Unless the owners are very heavy smokers and in the absence of cooking fats (etc), I do not sugar soap the walls.

 

[sparkwright]

No point cleaning anything if it is already clean - but a quick sand is worth the trouble.