Tersky, if you are not having any problems, then the pebbles do not need to be baked. The H2O2 will only kill some of the nasty little things that are floating around in the air, a disinfectant will kill off most things that will mess with your grow. I would not recommend using bleach or soap as they are very difficult to rinse out. A good rule of thumb when using bleach is, if you can smell it, then it is too strong to be used with your plants. I tried to clean some of the pebbles with bleach and could never get the bleach smell out of them, so in the trash!