When I was growing up, it was my job to clean the bathtub my brother and I used. Every week I would scrub the tub until it was shiny and the telltale ring around the edge was gone. But as hard as I scrubbed, I could never get the anti-slip foot grips clean.
As an adult in my own apartment, this foot grip cleaning problem continued to bother me. I tried many things, including soaking the bottom of the tub in almost straight bleach, but nothing could clean those darn anti-slip grips!
When I was doing my shower door cleaning tests, I learned something else: When the acidic cleaners, like Bar Keepers Friend and Lime-A-Way, ran onto the bottom of the tub, they perfectly cleaned the anti-slip grips! In my mind, this accidental discovery was similar to finding penicillin or inventing Wheaties.
The picture above perfectly demonstrates the strength of Bar Keepers Friend, my preferred cleaner. The left side of the tub has been cleaned with BKF, the right has been left dirty.
Another photo illustrates the failure of conventional alkaline-based tub cleaners to clean the anti-slip grips.
The left third of the tub bottom has been cleaned by BKF. The middle third has been left in its dirty state. The right third has been sprayed and scrubbed thoroughly with a common bleach-based cleaner. Although tub cleaners are generally alkaline because they cut through grease, they’re no good at penetrating the tiny crevices of the anti-slip grips. The color of the tub bottom has changed slightly, but not much.