That looks strongly like mineral deposits, but the way you describe the bottom sounds like mealybugs. I use straight lemon juice to remove mineral deposits from my plants, with paper towel. I warm the soaked paper towel in my hand first, just so I don't shock the plant, since I keep lemon juice in the fridge.
You can take a q-tip dipped in rubbing alcohol to wipe off the mealies, if that's what the white fuzz turns out to be. You may have to keep a close eye on it, and do that repeatedly, but mealies are easy to defeat if you get a good handle on them in the beginning, and stay vigilant about removing them regularly.
Since this thread is a month old, how are your plants doing now?
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