there is sometimes a metal cover in front of the rubber seals, you have to pop that metal seal off to get to the rubber seals. you can then pop out the rubber seals to expose the bearings and clean them, then put the rubber seals back in place. I take the metal covers off my bearings to make it easier to clean them, and just clean the bearings after every day of racing. But the post from jake17j about drilling a small hole in the hub sounds like a great idea to keep them lubed, but i wonder if that will let the dirt out of the bearings or not