There is a school of thought that base cleaners/wax removers should never be used on the ski bases and hot scraping is the only method to employ for cleaning ski and snowboard bases. The thinking is cleaners will absolutely dry out the bases and destroy the wax saturation level and optimal glide achieved through repetitive wax cycles. How much wax is removed is highly variable from zero to a fair amount depending on duration, how aggressive is the cleaner and how much brushing and elbow grease is applied.
This is an ‘old wives tale’ or hearsay at work (that endlessly gets perpetuated on the internet and via word of mouth) when it comes to the debate over using cleaners vs. hot scraping with a soft wax. From a technical standpoint sintered bases are basically inert and do not bond well with anything. The surface of the base in contact with the snow is amorphous and random in nature. Structuring the base creates lines in the base material and establishes a pattern, but the underlying material is still amorphous and random.
Wax (or base cleaner for that matter) only penetrates a very small amount into the base, about 15 microns and only where random voids exist. 15 microns is a very small measurement (1% or so of base thickness~15 to 20 microns is about 0.0006 to 0.0008 inch). How can base cleaner possibly “dry out” the base if it only penetrates 15 microns? The answer quite simply is it doesn’t. Base cleaner, or at least Briko-Maplus base cleaner is basically detergent dissolved in a solvent. The solvent almost entirely evaporates and the detergent works to properly clean the base. When you take your dirty car to a car wash do you wax it first or clean it with detergent and then wax it? I’ve tried both and the later definitely seems to work better.
A distinction should be made between paraffin and perfluorinated waxes. A specific base cleaner called Fluorclean should be used to remove perfluorinated waxes as it is designed to remove all traces of fluorine from the base. Hot scraping at best blends new wax with a combination of old wax and contaminants in the old wax. I admit you will notice some contaminants being drawn out of the base when hot scraping if the base is dirty, but the iron is not a magnet and does not magically remove all contaminants using wax as a conduit. Residual wax left on the base after hot scraping will still have undesirable stuff in it.
Additionally, duration and type of cleaners can be employed judiciously to expedite and provide clean bases, ready for the next coat of wax. The longer a wax remover or solvent sits on the base, the more it can cut into the wax and any contaminates. Also, a more aggressive cleaner can also be used to remove the surface contaminants in little time and use of materials while eliminating the hot scraping steps and mess. Diluted (1:5) household cleaners like Simple Green can provide adequate cleaning. Biodegradable citrus based cleaners can be great options for cleaning the base and removing wax when harsher solvent based cleaners are not needed or desired. For base repairs, base cleaners are necessary, coupled with some sanding and cutting of the base material.
So, back to the original question. The best way to clean the bases is the method that is best for you, your preferences, time available, costs or beliefs: either hot scraping, base cleaner or a combination. If you are concerned about base cleaner remnants on the base, you can also hot scrape afterwards or simply wipe off with water.
A caveat to keep in mind is that skis and snowboards tend to run better and faster after more wax cycles and time on the snow. So, more aggressive cleaning would require more wax cycles to optimize the glide than a less aggressive, more topical cleaning.