Read this article to make sure you use the right hydrogen peroxide

This next part is very important: Do not use ordinary hydrogen peroxide that comes in little brown colored plastic bottles. The stuff at the supermarket has stabilizers in it and contains a slight odor. Pure hydrogen peroxide is odorless. I purchase pure hydrogen peroxide from a local swimming pool supply store. Baquacil brand Shock and Oxidizer is the product I use. It comes in a one-gallon size blue colored plastic container. It is pure 27-percent hydrogen peroxide (no additives or stabilizers). You will have to dilute it with distilled water, down to 3 percent strength in order to use it in your home brew recipe.