Sure, you could always add the old WD-40 to your 608 bearings to get them go spin smoother and faster, but why waste money on the oil when you can actually make a noticeable change in your bearings? The tools that you shall need are a shielded 608 bearing (I got mine from https://www.amazon.com/Bearing-Shielded-Greased-Miniature-Bearings/dp/B002BBD6X4/ref=sr_1_3?ie=UTF8&qid=1487218581&sr=8-3&keywords=608+bearing), and a small flathead screwdriver (It should be about the size in the picture). Also, your bearings shall look much more cool afterwards. I used this on my fidget spinner that I got from Thingiverse (credit to LoveWaffle for the design): http://www.thingiverse.com/thing:1915419
There is a guaranteed mega boost in performance after you do this simple hack. In the end, they spun just as fast if not faster than a ceramic 608 bearing.
Step 1: Pry Off the Metal Shield
Stick your screwdriver between the shielding and the center ring. Make sure that the screwdriver goes in, but be careful not to damage the bearings inside. Carefully pry the rest of the shield off of one side. Repeat on the other side, and you should have a 608 bearing with the covers off (doesn't it look much cooler?), and two rather bent covers.
Step 2: Wash and Spin
I recommend washing the bearing out with rubbing alcohol before using it so that you can get dust and grease out of it. You may oil it now, but I prefer just to leave it with no oil because it is just too messy. I was blown away by the performance of it compared to the same bearing with the shields on.