Zeros way of doing it with the grease is a good way of doing it back on pg1. It's how you do 1:1 scale car wheel bearings and not a bad way of doing it.
I use oil. Yeah racing bearing oil. I simply lay them out on a wad of paper towel. Flat preferably and oil em up. Let it sit for a minute. Wipe and re mount. When theyre crunchy yes toss em and replace. Lol.
I do not recommend running without the shield. Replace the shield and run em. Don't run em open ended.
I run on clay indoor and asphalt outdoor.
hths you
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