Wear gloves when mixing this, the hydrogen peroxide wont hurt you, but it could bleach your skin at full strength and itch a little:) also, don't use the peroxide on your hair:)
Mix peroxide, water and oils of you choice. the cram consistency of the peroxide will help it cling to the moldy areas of your tile, and just like a scrape full of germs, the spray foams on contact with the mold, wiping it out fast!
I usually buy a 6-10 oz bottle of peroxide, make the spray, and dump the rest into a running tub to "bleach" out the rust stains and I let it soak for 15 minutes before I scrub!