I've noticed that meatballs are one type of food that often tastes much better the next day. So whenever I make meatballs, I make lots of extras and put them in my fridge to allow the flavors to "develop".
However, when I warm the meatballs up in the microwave they sometimes get dry or have slightly tough and rubbery spots -- especially on outside edges.
What is the best technique to re-warm / re-serve meatballs that you have made the previous day (or a couple days prior) so they stay moist and delicious?