What You Need -
1. Glass Jar
2. Carburetor Cleaner
3. Synthetic Grease (I used Mobil 1)
4. Something with a very fine point like an exacto knife
For the glass jar, i just got an old pickle jar. DO NOT use a plastic container or the carburetor cleaner will eat away at it. I went to Advance auto parts and got the cheapest can of carburetor cleaner I could find. The synthetic grease is normally for wheel bearings, you can get them as cheap as $2 or so. I went with the Mobil 1 version, not sure if there is a difference. You will also need something with a fine point to remove the shields, and a napkin or a towel to dry the bearings.
Start by removing all of the bearing shields. Try to dig the tool into the edge of the bearing shield and pry up, be careful, these are easy to damage. I left the bearing retainers on while cleaning. Once that is done, put the bearings in the jar and spray the carburetor cleaner into the jar. (Do this part outside; there can be a lot of fumes.) I usually spray enough to cover all the bearings. Then shake for about a minute. Shake for more if you feel the need, but carburetor cleaner is strong stuff, a minute should be good for pretty much any set.
Now you need to dry the bearings off. Open the jar and take them out. Tap them on the napkin to get the carburetor cleaner out faster. Let them dry for a couple of minutes. Once they are dry, try spinning them to see if they spin freely. If they still do not spin freely after cleaning them, they probably are not usable. If they do spin well, and are completely dry, you can move onto greasing them up.
To grease up the bearings, you need something to apply the grease. I used the same tool I used to remove the bearing shields. Use a little less than a pea size amount of grease per bearings, but do not apply it all at once. Use the tool to apply a tiny bit to each ball bearing and then roll it around and work the grease into the bearing until you can’t see the large chunks anymore. Once all the grease has worked its way around, you can pop the bearing shield back in and your bearings are ready to go.