I got my new Naniwa Super Stone today and as usual it had a sticker in the middle of it. What do you do? You peel the sticker off and if your like me you wash it where the sticker was. Bad idea! Why? The soap I used if it matters was the foaming hand soap in the bathroom but the result is my point. Where I applied the soap an rubbed it the stone immediately became thirsty! I noticed this right away and applied more water and there was a definite line where the soap stain ended and the stone stopped soaking water like a sponge. So that tells me not to use soap to clean my hones because in making water wetter it makes the stone thirstier and alters the properties of the binders. I was able to rinse and lap the soap away since I noticed it so quickly but I did make a large puddle of slurry. Let me reiterate LARGE! So if your Naniwa seems thirsty ask yourself if you used soap to clean it and then you might know why. It doesn't soak up water 1/10 as fast if not affected by soap. I assume this leads to swelling also.