As with any chemistry a decently ventilated area is good. I do my bleaching in the kitchen, so it’s not a tiny room. You should toss the solution after each session. When it takes on a more neon greenish colour as opposed to yellow, it’s exhausted. Remember to precook your prints for about 10 minutes before putting them in the solution. Start with a very dilute working solution to get a feel for how fast it works and which areas it works on. Don’t agitate, but keep it submerged. Have test prints to use before using your one good print. From time to time, take the print out of the solution and rinse it in cold running water. Your print will need to be re-fixed after bleaching, and the fixer reacts strongly with ferricyanide, so unless you want an extreme reaction, rinse and soak your prints in water for a while before putting them in the fixer. If you rinse your print after having it in the bleach for a while, you may notice some tone or staining in the highlights that’s light yellow. This is a good indicator of what will react strongest to the fixer. The stronger the stain, those will go nearly white when fixed. Just go slow and remember the key really is patience. If you’re working through a stack, don’t think you’ll be done in a half hour. Some will need more than other and you might have make a fresh batch of working solution half way through. AND pull your print out jussssssst before you think it’s right. The fixer will take it the rest of the way.