Removing Dye from a Fiberglass Tub

I don't KNOW if this would work but maybe if you made a strong bleach solution and filled the tub up to the dye line and let it soak for a few hours...maybe.

I did a similar thing a few years ago and it took me weeks of soaking in bleach and or scrubbing the residue with oxy clean. I messed mine up when I tried to make purple soap using the melt and pour glycerin soap with red and blue food coloring. Each time I took a shower a little more charcoal gray stain would appear. Nasty looking mess! I finally got it clean and I will NEVER do that again.

Not sure if it will work, but here are a couple suggestions: First try baking soda as you would cleanser-it shouldn't scratch the fiberglass, test in a small area first. Next, you can try a thick paste of baking soda mixed with dish detergent. I dyed something in a white enamel sink and this took it out, and also out of a stainless steel sink, where I couldn't even see the color residue. The baking soda almost seemed to absorb the color particles. Might take more than one application, and with all the scrubbing a sponge will probably be more comfortable. Good luck!

I agree with the baking soda and liquid dish detergent.
It may take a couple of scrubs but it worked for me.

I just made my first tie dye tee shirt. Black dye all in my fiberglass tub. My wife was flipping! So I took baking soda and Ajax liquid soap. I sprinkled the tub with the soda then, where the dye was worst, I put the soap. With a hand brush, I scrubbed the soap in and the dye started to disappear. Not event 10 minutes later I was back to watching TV. It works 100%!

Clorox bleach spray (which is diluted for multipupous for you) and a magic eraser