Bathroom tiles

They are a pain to clean.

The grout (plaster between the tiles) is a porous substance, where water can collect, and grow mold and mildew.
The mold would be deep in the grout, so Elbow grease does not help.

These tips are supposed to work on the stubbon bathroom mold:

Dilute vinegar with water and spray on tiles.
Use baking soda as a scouring powder, and scrub away with a tooth brush
Dilute bleach 1:9 with water, spray on tiles, wipe when it becomes white. (Not ecofriendly, but helps use up the bottle of bleach you already have.)
Use a cotton ball to apply tea tree oil on the grout, do not wipe (caution: Tea tree oil is a known endocrine disruptor, giving rise to man-boobs in teen boys. God forbid! I can live with bathroom mold any day.)

The first two tips seem the best and eco friendly, I am trying them out this week.

Update:
I cheated. My baking soda is over, and I have not bought vinegar yet, so I used bleach.
I had to spray twice, to get the mold off. The fumes were really bad and I kept the room closed.
Then I rinsed it off and used an old toothbrush to work away the remaining mold.

Now the mold problem is somewhat under control, and the bit that remains is under the sealant, on the grout.
I wonder how I'd get them out.

I found this link today, and the tips are simple enough.
http://www.mrscleanusa.com/tips/cleaning-bathroom-tile.html