The Microwave thing might help the mold, Everybody\'s experience seems to be a little different. My paper seems to last longer when I micro wave it. The bleeding that I get is with the Dark Browns and Blues. My brand is a Masterson and the outside of the paper package says that bleed through on dark colors is normal. Most of mine occurs with Prussian Blue or a Dark Brown. I use my palette every day and I have found that I am constantly changing the water and the paper and the sponge in that order. I have not ever seen the mold but I have seen its effects the sponge will fall apart. I tried the distilled water, and you might have better luck than I did, I just found that buying a special jug of water got to be a pain, no slam on people who can manage this lol I\'m just forgetfull so I switched back to tap water. The best thing about the Palette has already been said. It helps! My blending, mixing, and general paint waste has all been improved. I wouldn\'t switch back to not using one for anything.