Not bat at all really.
Buy a bearing packer, unless you are fond of marine trailer bearing grease all over your hands.
Check the spindles really well, make sure there are no gouges in them, that woud ruin your next set pretty fast. Replace the seals too.
Here's a great index of how to's:
http://www.championtrailers.com/techsup.html#technical_support Replace the seals too