purigen regeneration

Okay fishy friends- have an Innovative Marine 20G set up that uses the special filter socks- they have the black plastic mount on them and the filter sock itself doesn't detach. I am determined to find a way to clean them because it is so wasteful and annoying that you have to buy these each...

I have never used purigen, because I'm afraid the regeneration process might easily go wrong. Do you need to be super careful with the residual chlorine from the bleach? Or you're always gonna be fine as long as you add the correct amount of dechlorinator and then rinse? Are there any "horror...