I want to make a couple of those rice-filled microwavable bed warmers. I’ll make the inner sack out of cotton, but I’d like the outer sack to be polar fleece. I can either hand sew one edge of the fleece to remove it to launder the cover and then re-sew (the easy way given I won’t need to launder it very often) or sew in a Velcro strip and remove the outer sack every time before I microwave.
Which is better? Am I running any risk if I repeatedly microwave polar fleece?
Also, what fabrics are microwave safe? I know anything with any metallic content is probably not a good idea, but some websites say to not use any fabric that isn’t natural (cotton, linen, wool, etc.)