How to clean fiberglass tub & shower that has soap scum, smoke & iron

http://lancaster.unl.edu/home/articles/2009/fiberglassclean.shtml

Start with scrubbing the shower soap scum on the doors with shampoo, dish liquiid, or soapy substance, with a scrungie sponge. This sponge has a rough side, then rinse. Spray with straight vinegar, scrub, rinse. The shower that is fiberglass, may be able to use Soft Scrub. Check with the manufacturer or your user book, for the right cleaner to use. Good Luck!

I swear by liquid comet and a Mr Clean Magic Eraser! It does wonders on my run!

Formula 433 (Natural cleaner from Green Virgin). I use it on everything. Use it to clean my marble and fiberglass shower. My fiberglass whirlpool tub. I use for everything and don't have to worry about my skin as it won't harm. I just used to get dried blood out of my sheets. My hubby has the old skin now, that cuts and bleeds easy. Probably was on there for days before I saw. All came out easy.

Barkeeper's Friend. Make a paste, apply, let sit, scrub.

Here' a post that might help https://chascrazycreations.com/clean-bathroom-natural-products/