What cleaning product to get black marks of white fabric?

[CandleMug]

I think it could be mascara but not sure and it’s on a white duvet. Can anyone recommend something to use that will get it off please as I can’t put it in the wash as it won’t fit.

TIA

Eye make up remover or micella water might work if it is make up. And/or take it to a launderette and put it in the big machines they have there (and massive tumble dryers). TBH if it's just the duvet and not a duvet cover, and the mark isn't anything really gross I wouldn't worry that much as no one will see it presumably?

If it's not a big area, submerge in warm water and scrub on a mix of toothpaste and washing up liquid (degreasing quality of WUL as good as you can find). an old toothbrush is the best thing to scrub with. Rinse through and keep doing it.
DD cleans off teenage quantities of very black mascara on reusable towelling cosmetic pads. It gets that out.

I clean marks on the outside of a duvet I don’t want to/can’t wash by gathering up the bit of cotton cover with the offending stain into an elastic hair band, then (carefully!) handwashing and rinsing the resulting “ponytail” with whatever detergent /stain zap, is suitable. I then wring out the ponytail as best I can, then maybe dry it a bit with a hairdryer, remove the elastic and hang to finally dry out, preferably in the sun - our Chinese laundry conservatory is ideal for this.