I just ran it through again with some Le Blanc and oxy powder. I did some reading and found that chlorine bleach can actually cause yellowing especially if you are on well water, which we are.

I have been using Charlie's Soap for maybe ten years and never had yellowing in white fabrics. My guess is this was defective when you bought it, but did not notice the stains until later?

A year or or two ago, I bought some cotton sheets at Costco. They looked nice, light and bright, but after a couple of washings they turned gray and dull. My LLBean percales never did that and still don't, so I wonder if ther is some sort of brightening or whitening chemical applied to whites at the factory that washes off quickly. We cannot trust textile manufacturers.

I’ve never had an issue with the Charlie’s either. I’m pretty sure it was a result of the finishing treatment at the factory. I think the oxy I’d doing the trick.

Larisa is right. The brand Oxiclean is about 50% sodium carbonate (washing soda) if your using a liquid detergent it's fine but powders already contain a large amount of washing soda. No good reason to add more. Washing soda can be the devil to rinse out. Professional laundries use a fair amount of it because they have to wash things fast..no time to soak or long cycles so they boost the PH with washing soda but than they also use what's called a *laundry sour* to neutrilize the carbonates. Carbonates not properly rinsed can cause yellowing expecially when exposed to heat from the dryer or ironing.

I prefer using pure Sodium Percarbonate(oxygen bleach) instead of Oxiclean. Much less carbonates and cheaper as your getting much more of the active ingredient instead of 50% fillers. You do need to use hot water to activate it as it doesn't contain a bleach activator. But I've done cool water soaks in the sink with the SP on whites overnight and had excellent results.

If this was brand new, I would return it and get a replacement from Ikea. I have the same duvet and no yellowing... and stains come out just fine with one of the Tide Powders or with the now discontinued in the US Persil Pearls. I've even used Grab Green pods on it, also good.

Looks like residue from the soap or whatever treatment was on the fabric. I would guess that the duvet didn't get thoroughly rinsed.