Now that we got the nerdiness out of the way, let's get back to it. We submerge our board in water. Let it air dry for a few minutes and then we go right back to the 220 grit orbital sander. This process pulls up the grain a bit (think of a static charge making your hair rise) and allows us to easily knocks off any that hairy feeling.
Now that your board is super smooth, we submerge it in food-grade mineral oil. We do that so that your boards capillaries are filled up. Food-grade mineral oil is a straight chain hydrocarbon. It has no reactive sites, and therefore never dries. When applied to end-grain cutting boards, it penetrates the wood until it can go no further. This is why after you apply mineral oil, you'll notice the board soaking up the oil until the surface is completely devoid of liquid. That means you can add more oil until it no longer soaks up the mineral oil. That is what we accomplish by submerging the board in food-grade mineral oil.
Finally, we finish up your boards by popping on 1/2" tall rubber feet. The feet serve multiple functions. #1, they absorb shocks. This is good for your arm and for your knife. #2, they keep your board's bottom dry which reduces the possibility of warpage. #3, they make it easier to pick up and maneuver your board. #4, they maximize board stability. #5, they are totally non-slip, meaning you no longer have to use a soaked towel below your board. This also helps ensure your board won't warp.