60 wash if they are grim looking then I soak them in the bucket overnight with 30ml washing powder and tea tree oil. An hour or so before they go on a wash half scoop vanish pink. Then I strip wash them with soda crystals. I normally save up preloved purchases till I have a full load for this reason.
I use bio d sanitiser in my nappy wash each time sanitiser at 30 degrees for any thing I buy pre loved I do the same but rinse a lot but only because we can't use any washing powder due to sensitive skin so have to rinsevit our from preloved stuff I don't soak anything just a cold rinse first in the machine.