Sounds like a great topic for a video…
Dustin Courter taught me some great tips for bearing maintenance, and the Kart 360 video on the subject touches on it.
Maintenance somewhat depends on the bearings you have. But generally, a solvent and cleaner is useful to remove gunk, and then a simple bearing lubricant is also good. Lots of people here hate tri-flo, personally I love to utilize it but it can attract more dirt.
Simple thing to do is if the bearing has seals still in tact, leave them in tact, clean the exterior, and re install.