Mould/mildew stains on PUL?

One of my Flip wraps has sprouted small black spots, I am assuming it's mould/mildew stain. I discovered it after it had been airdrying on a rack for a couple of days.

Is there anything I can do? I did a search and see people have had good results with Milton/bleach solution on stained fabric, but this is PUL and I am afraid it would damage it (as I once ruined a food-stained Airflow by attempting to clean it with Milton). The marks on the Flip wrap are visible on both sides.

If I don't attempt to clean it, will it be ok to use or is it only good for the bin?

I wouldn't use it tbh. Are you sure it's only the pul cover? It wouldn't have got mould on the airer so it might have been in the nappy pail.

I wouldn't use it.
We got similar marks on a vest that we'd dumped in the nappy bucket after a nappy leak coz it was going to go in the nappy wash - however it was at the bottom of the bucket and by the time we came round the nappy wash it was covered. Didn't come out in the wash - so binned it.
I didn't want to take the risk personally.

Thanks ladies. It completely puzzled me because NOTHING else had marks on. I wash the bucket out with boiling water every time I empty it as well. I'd understand if it was a rogue wrap that had been stuck in a bag and not washed for ages, but it hadn't. Totally puzzling. I actually rang up the shop I bought it from, and they suggested washing it in Rockin Green, and sent a sample; as I'm planning to strip wash some nappies on Monday I will stick it in then, and if the marks don't come out I'll get back to them. I also rang Baba Me, who supplied the shop I got it from, and they mentioned something about possibly getting a replacement sent, since it's less than 1 year old.

just to update - I tried the Rockin Green strip, and then a dishwasher tablet strip, to no avail.

so I posted a question on the Flip Diapers Facebook page, and got a response from Flip - suggesting I try 60ml (1/4 cup) regular chlorine bleach in a hot wash. have just done it and the nappy is clear.