I know this subject has been discussed several times in the past but I just wasn't paying attention. Now I need to know. I'm having a set of running gear rims sandblasted which probably will result in flecks of rust remaining in the pits. Here's a photo of one of the rims. Ignore the galvanized round metal on the hub - that's my solution for keeping the sand from the bearing races that are inside the hub. I've cut those round metal pieces and placed a round piece of innertubing under it on each side of the hub and held them tight with a 1/4" threaded rod. Hope it works. What should I do with the rims prior to priming when I get them back from the sandblaster?