Awesome Tub Cleaner
1/2 c Dawn Dish Soap
1/2 c White Vinegar
Heat vinegar in microwave for 90 seconds.
Pour vinegar into spray bottle.
Add dish soap and close bottle
Swish gently to mix.
Spray on tub (and tub walls if desired)
Let sit for 2 hours.
Wipe down tub (and walls).
Admire your shiny tub.
I didn't have to scrub the tub but I did have to wipe firmly over the area. It came completely clean with little work. Vast improvement.
The wait time is important. Don't skimp.
Don't breathe while pouring warm vinegar into bottle. It won't hurt you but the smell is sinus clearing.
This is not good at whitening stained caulking, but nothing really is.