I made a wonderful soap used to remove soap scum and crud from brushes and stones. It is 100% coconut oil with a splash of glycerin (for the brushes) and a dash of citric acid (to ensure quick lather and help with scum). I made one batch with 100% KOH and one with 100% NaOH, if you want it soft enough to load into a brush then I recommend using all or mostly KOH. The all NaOH soap is the hardest substance on earth once fully cured. I use it to rub on stains and rub on stones. It is super slick and could be used like Dawn but i have yet to even try that.
I regularly use Simple Green (50/50) on my stones. I find it does a good job of keeping them clean and i can use it whether i have been using oil or just soap and water. I have read tales of people boiling their stones in simple green to remove oil build up, I take this to mean stones can handle quite a lot. Still, if the stone has got the mojo i understand you wouldn't want to do anything to change that.
dkeester observed that honing is as much art as it is science. I would argue its ALL science but how we humans get there is an art. I remember repeatedly asking "what does a bevel look like when it is "done"?" and being frustrated when none of the "experts" could tell me or show me. For the longest time i felt like honing was a skill relegated to a secret community and i wasn't invited. After watching a couple of DrMatts videos it became clear to me, he explained the science behind it and it all clicked. Now that i understand the geometry of it all the major variables are understanding stone characteristics and the techniques that lead to better results.
