I recently used a mineral deposit remover for the very first time. I purchased the Gyeon WaterSpot, after a healthy discussion with many great detailers on its comparative value to detailing clay. The backstory; there are two common schools of thoughts on the effect detailing clay has on your paint. One group would say, expect detailing clay to scratch your car requiring machine polishing to remove damage. The other side says with appropriate use it will never leave any marring. My views leaned towards the latter, feeling comfortable using a mild clay bar with plenty of lubrication and folding the clay consistently to a clean side upon inspection. My views have evolved somewhat in accepting there can be some marring regardless of your level of care in the use of detailing clay. This left me open to exploring a type of product that could lead me to, not eliminating, but reducing the number of times needed to clay my car.
At the time I received this product, I just happened to discover the top panels of my vehicle have been air mailed with water thanks to the work of a pressure washing company. This left me with water spots that had sat for a couple of days.
I used the Gyeon WaterSpot on the front horizontal panel of my car. A week later I washed my car and applied Blackfire Crystal Seal. As I spread the product on the top of my car, the one horizontal panel that I did not use a mineral deposit remover, I could feel a roughness to that entire area. The other areas of my car were smooth, including the front panel. It was another glaring sign the product did its job and what had officially sold me on this kind of product.
Now I do believe whatever marring that takes place with a medium to mild clay bar should be minimal with proper use and constant lubrication. If I only had to choose between the two, the clay bar is more of a necessity to adequately remove all of the above surface contamination. With appropriate use of detailing clay removing all of the above surface contamination is still worth minimal marring that I still believe for the average car enthusiast can be masked with micro fillers of your favorite paint cleaner like Blackfire Gloss Enhancing Polish or P21S Paintwork Cleanser.
But I am not making the case for one or the other, I am suggesting there is a place for both products in your detailing bag. With the mineral deposit remover, you now have something to address what regular washing did not remove with something a little quicker and more gentler than detailing clay.
I also would like to remind users to be careful to make certain this type of product is removed completely (rinsed off) from the paint surface. Just like you do not want to leave something alkaline like an APC on your paint, mineral deposit removers are very acidic.