Hahahaha. Loved this story!!

Lol! Well, that will make some of them decide not to buy rolls! is what I thought when I read that.

Maybe??
 

I buy the big bolts too and have been working my way through a white cotton 90 inch by 40 yards and so far it's been great. I keep it in the finished basement because that's where the layout tables are where I baste.

Today I unrolled it to cut a piece and there are stains on it that I think are mildew. I have no idea where it came from and the bolt hasn't gotten wet. It doesn't smell. The stains were on an inner layer. I attached a photo.

I'd like to get rid of the stain and still be able to use the batting. The cost of the roll has gone up $100 since I bought it.

I am thinking that might be a manufacturing stain - if it does not smell and it has been dry - I would use it.

If it is washable, I would soak it for a couple of hours with a dab of mild detergent, spin, rinse, and dry gently.

My machine will let me do that - don't know if yours will.

If the stain is still there, and it would not show, I would use it.

P.S. Read the instructions. Some battings should not be washed before they are quilted.

Can't Wash
 

Found the instructions - it says no washing until after it's covered - in the project. It does say you can soak to pre-shrink - but I don't want it to shrink at all if I can avoid it - I LOVE the way cotton batting shrinks up in the quilt with the 1st wash after quilting. I love the finished crinkled look and it hides my mistakes.

The piece I am using is pretty big - about 90" x 80" so if I soaked it in cold vinegar water it would be very hard to manage and get dry. I would like to avoid that.

I'm thinking of trying to blot the stains with a little vinegar-water mix. If it is mildew I would like to see it die before I encase it in the quilt. The quilt is black/gray and yellow so the stains shouldn't show, I just don't want the mildew to spread when washed and used.

mildew would normally not just be in one spot - meaning you should also see some where it was touching the next layer on the roll. If you don't find any evidence of that, I'd figure it is more likely a dirty spot that got there when it was being rolled.

I buy almost all my batting on roles, and have found dirty/damaged spots occasionally. Most often I set the piece aside for a smaller project, and cut a new one.

Thank you for your input as well!
There are spots here and there - it has many characteristics of mildew except I studied it in the morning light and it looks like a dirty area.
I tried blotting one small area with vinegar water and the only thing that happened is it looks more clearly like a stain from manufacture.
Since I often do quilt-as-you-go and use small pieces I decided to put the piece aside to cut around the dirty area later. I just cut a new piece for this quilt and it's all nice and clean.

I have some batting here that is about 3 years old and it is still a good as the day I bought it. It comes off the roll great and works great I am using some right now to make Oven Mitts. I store it in my extra bedroom.

Cut the stain out and lay a scrap of batting over the cutout. Use batting tape to secure it and then quilt with it.