What fabrics can be microwaved?

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.)

Polarfleece is made from the plastic polyethylene terephthalate (PET), which can release antimonythrough microwaving. Not to mention, it might melt or catch fire. Please don’t put polarfleece in the microwave.


Is it safe to put polar fleece in the dryer?

A number of DIY sites talk about making cheap hand-warmers and heating pads with polar fleece, and you can buy such from sites selling handmade crafts.

However, I haven’t found any commercial products along those lines which seems to support what xnylder says. I wouldn’t do it.

The only thing I can say for sure from my poking around is that anything made from cotton should be fine.

Yes, but not on a super high heat. Also, throw in an anti-static dryer sheet.

But I thought polar fleece was an insulating fabric! So wouldn’t using it as an outer covering just reduce the amount of heat from the rice that is transferred to your bed?

Seems like a smooth covering, like cotton, or better, a thin silk, would be more effective.

My wife made one after one she bought burst. She made an inner bag from cotton and sewed it tightly to contain the wheat (or whatever it was). Then she made some loose slip covers like pillowcases to fit over it so that she could wash them. Still working after several years.

All the rice heating pads I’ve seen have been made out of terrycloth towels. If you really want polarfleece, maybe you could have an outer cover that you put the warmer into after heating it.