Good grief and a half! Our bathtub floor was giving me a serious headache. It's got a very textured base where dirty, soapy water just builds up and sticks down in all those crevices. It was pretty clean when we moved in, but over past 20 months just gradually keeps getting worse. NOTHING gets it clean. I have tried:
Brillo pad (which is usually what I use to clean sinks and tubs/showers)
Magic Eraser (you'd think this one would work)
Various chemical cleaners: Kaboom, Clorox w/bleach, etc (ewwww...harsh smells)
Toilet bowl cleaner
Ammonia (I had used straight ammonia on my textured old vinyl kitchen floor several years ago and it worked wonders, thought maybe it would get into this texture and bring up the dirt too)
When I googled cleaning a textured tub floor various comments on various pages swore by the above. None helped me a bit.
Scrub scrub scrub and it just won't clean. You'd think something would lift up that dirt! Finally, I found a you tube video I watched of a really grungy shower floor (but it wasn't really textured the same as mine) and I tried that method.
Sprinkle down baking soda, cover with an old towel and pour boiling water over it. Let set until cool. Use old towel to scrub up dirt stains. In her video that took most of it up. In my case, it really did nothing. Her second step was to heat up 2 cups white vinegar and 2 T. Dawn dish soap in microwave for 2 minutes. Spray floor and let set for 30 minutes and scrub up with a brush. Ok, now we are finally getting somewhere. Not all the way there, but a huge improvement. The half of the floor farthest away from drain/spout got completely clean now. The other half was about 50% better. I did a second spray of the hot vinegar and dawn and let it set a half hour. It's finally clean now! I didn't want to leave a dirty tub/shower for whoever buys this house.
Things I've learned I don't want in my new house, from this house:
white kitchen sink. It stains too easily (though Cascade dishwasher detergent sprinkled on and then scrubbed with a sponge works pretty darn well)
textured shower/tub floor - UGH!
an oven with no venting for broiling. I can't broil steak or hamburgers without setting off the fire alarm