These bags work great for brewing. I've also repurposed the one from my old kettle for making soup stock!
I put a small lift in the bottom of the pot so that the bag wouldn't touch the bottom while the flame was on, filled the bag with all the goodies for stock that are normally a pain to separate from the liquid, filled with water, and simmered on the stove all day. I was able to just pull the bag to separate the bones and spent veggies.
I drained the bag in a big bowl with some gentle squeezing when it was cool. After dumping it, it required much more cleaning than is necessary for beer, but wasn't difficult. I washed it good then soaked it in a dilute bleach solution.