Should I worry? (Packing my A500+ ... for now)

[Damion]

In addition to what everyone else said, a little baking soda/distilled water with your toothbrush works very well to clean off the corrosion. Rinse everything with distilled water when you're done cleaning.

Replacing all corroded components is also a good idea, albeit a PITA.

[Damion]

Well, one reason I don't like the dishwasher is because it blasts all the labels off the motherboard.

I have used a pressure wand and hot tap water a few times on nastier messes (removed the chips first), but then you can keep a paper towel or something over the labels... and rinse with distilled water either way, I don't like the idea of letting tap water dry on the PCB...