When it comes to stock racing its absoulely necessary that all bearings move as free as possible.
I would like to give you an example how i prepare my bearings before a race weekend!
First of all get a clean workingspace, i perfer to use an extra cover like Wypall.
put a sharp cutter between the sealing and outer ring of the bearing
lift the sealing carefully by putting down the back of the cutter, slowly so you dont slice your fingers
I perfer to do it only on one side
put all bearings in a bearing cleaner, you can also use a film container
fill it with Motorspray and then „shake, shake, shake“
get all the bearings out of the can, if there is still any grease left, do it again (with fresh Motorspray!)
after the bath in the motorspray, get the cage out and pour the bearings out. Let them dry!
You also can spin them on a tweezers, a pencil or the end of a brush to get the last humidity out of it.
After that get a drop of high qualitiy ball bearing oil in there and spin them again to make sure the oil is all over the balls on the hole bearing!
now you can put your refreshed bearings back in your car, with the sealing side to the outside to make it harder for the dust to come in.