Using Peroxide to kill mold?

I have watched on video's where growers use peroxide to kill bacteria on plants and such in aeroponic systems..

I'm growing in Perlite / Vermiculite and some of the clones had a little mold on the rockwool cubes from the incompitent growers excessive use of water in the cloning process..

Question being what ratio's do you guys think will kill the mold but not the plant??
I am aware this will kill the beneficial bacteria as well as the bad stuff..
It really needs to be done as it is spreading onto my perlite mix and this is a situation which could turn bad quite quickly..

The product i bough was Hydrogen Peroxide Solution @ 3% strength..
Which says it can be diluted to an equal amount for use as a disinfectant mouthwash.

Any advice would be great guys