Mr. A was hired to do a cleanout a couple of months ago and the bathrooms had been neglected for quite a while.

I knew vinegar and baking soda wasn't going to do the job, chemicals would be required. Since I use chemical cleaners as little as possible, I wasn't sure what to get to do the job.

This is one I tried; while it did a fairly good job on the soap scum built up on the shower walls, it didn't touch the orange calcium/lime buildup in the toilet bowl: CLR Bathroom & Kitchen Cleaner

I tried this one as well, it didn't even work on the soap scum. Kaboom Shower, Tub & Tile Cleaner, 22 Oz

This is the one that actually worked.  Zep Shower, Tub and Tile Cleaner.  This is a commercial product.  It cut through the soap scum with no problem, just spray it on, leave for about 15 minutes, come back and rinse and it's sparkly clean.  I'd been scrubbing on the orange colored calcium deposits in the toilet, to no avail, until I sprayed on the Zep and let it set for a while.  I did have to spray and let it set several times. Mr. A had already decided to replace the toilets but I was able to get them cleaned until they sparkled. After it worked so well I decided to try the ring buildup around the water line in my own toilet at home, and it ate through that within minutes of spraying.

Interesting, I just noticed that Amazon has Zep tub and tile cleaner listed under Health and Personal care products. Heh.

Oh, and pumice stone or griddle cleaning screen also work well but I find that I need to be feeling energetic in order to use them since they do  require elbow grease.  Do be aware of the material you are cleaning when you use the pumice stone or griddle cleaning screen as it can scratch.   Toilets are always porcelain, so you can scrape to your heart's content. However, often sinks are not.  My mother-in-law has a janitorial service and made the terrible mistake of using the pumice stone on a bathroom sink the material of which was severely scraped and damaged. Luckily the business had been a customer of hers for years and they didn't get upset about the damage.

White vinegar is my favorite way to clean the toilet, I just pour in a few capfuls, let it set overnight and it cleans up very nicely.  Unfortunately the ring around the water line isn't affected by the vinegar in the water. We have really hard water so it's a constant battle to keep the buildup from building up!