I know it feels totally weird, but it works. It does knock a lot of crystals off, if it didn't make a scummy layer of mildew on top I would make hash out of it. Even though that mildew is dead, it's still kind of gross to make a concentrate out of it. That is a lot of peroxide, like a whole lot, but I guess that is what it takes to get it out of those really dense ones. Did you see that Jorge Cervantes video and how he did it?
And you can mix baking soda with water and make a killer pm spray. Products like Green Cure sell for 15 dollars are more for an 8oz tub, and it is just sodium bicarbonate and a detergent. So, baking soda and a drop of dish soap will do wonders. But be very careful mixing baking soda, I have heard nightmare stories of whole crops dying and frying from baking soda, make sure you research application rates, and make sure you use whatever brand that person recommends. I just used Green Cure because I like that it was easy and my inner lazy man was screaming, kind of feel dumb now, but I do like how easy it is, I really do, lol.