when i put my 1000 threadcount sheets through after I got them I used a bit of washing soda in the pre-wash, then put them through a normal cycle (with a mix of nappisan & detergent) then vinegar in the rinse & I then put them through for a 2nd soak & rinse in vinegar.

I bought 2 sets, am just waiting for a nice sunny day ALL DAY to do the 2nd set.