Hi Jesus289. I am understanding that you want to find out the valves of your engine that is armed, I do not know the procedure with hydrogen peroxide, to tell the truth I did not have news of it. To do that cleaning at least you must remove the exhaust multiple to be able to firm and that the material falls abroad, normally wash with warsol or diesel. LUCK MIGUEL
I never listen to that procedure, I suppose it is to avoid disassembling the cylinder head. In my case, the best way to decarbonize the valves is to draw the cylinder head, take out the valves and clean them. It is slow, but it is safe and keep in mind that it is the best.