Electric tea kettle with a little water – takes maybe 1-2 min to heat up (preferably NOT boiling!) to be warm enough to pour over bit. Have tried the under-the-jacket method with no luck and I just don’t give off enough body heat, apparently. :lol:
https://www.smartpakequine.com/the-bit-blanket-10793p
just bought this and LOVE it!! plug it in while you groom and it’s ready in minutes, without the hassle of those little packs that you have to replace or remember to boil to use again. Just need an outlet no microwave 
And you don’t have to worry about over heating. It stays warm for quite awhile after being unplugged too if your electricity isn’t right next to you.
Oh, it comes in a variety of colors too!
I do the rice in an old cotton tube sock, microwave and then put in small thermos container (like for soup) to bring it to the barn, I hang the warm rice sock over the bit while I groom, and the bit is nice an warm when I tack up. Apparently the warm rice smells pretty nice to the horse, because if I leave it hanging in his reach he usually tries to steal it. He’s pretty happy to take the bit when it’s time to bridle up. It’s cheap, lasts about a season, and easy to replace when the rice starts to smell funky (which it does after multiple reheatings). And who hasn’t got a basket or bag of socks around that have somehow lost their mates in the dryer?
