We have a glass shower door and very hard water. I was constantly looking for a product to keep the calcium buildup cleaned away. I had tried a lot of harsh products before deciding to try Method brand tub and tile cleaner.
Method makes cleansers for all surfaces that are made from natural products and are biodegradable. I thought that any cleanser gentle enough so that you don't have to rinse the surface after scrubbing it would not be effective enough to take care of the buildup on my shower door.
I was wrong! I thorougly sprayed the surface and let it sit for five minutes. I wiped the door down with a regular washcloth and the glass became clean.
Best yet, there was no harsh fumes and I wasn't worried about getting the cleaner on my hands or feet as I stood in the shower cleaning it.
I have since tried other cleansers made by this company and have been equally impressed.