What is scrim?
 

What is scrim and is it good or bad? I found a 30 yard roll of Pellon cotton batting with scrim for $113 at Walmart. I have use their batting before, but never noticed the scrim.

scrim is a very light material adhered to batting to help hold it together.

Warm and Natural has a scrim Here's a good explanation from their site (under "general")
https://warmcompany.com/content/faq

And a few more opinions at http://www.quiltingboard.com/main-f1...g-t187747.html. I just noticed from the Warm & Natural link that they don't recommend using 100% cotton batting in the microwave. What should I use when I make my next baked potato bag?

They don't recommend THEIR 100% cotton batting because it also has a polyester scrim.
Pellon Wrap-N-Zap is all cotton:
http://www.joann.com/pellon-wrap-n-zap/10706869.html

Thanks everyone! Learn something new every day!

I purchase 100% Warm and Natural White Cotton batting that is needle punched from Craftsy.

Check out Warm and Plush for microwave projects..my quilt store called the Warm Company and they said it was ok for microwaves. It doesn't have scrim and the label says 100% cotton NO scrim. Their other products all seem to have a percentage of polypropylene. But it is quite a bit heavier.