Best Wheels

One of the little wheels on the car doesn't touch the track.
Should I take a toothpick & clean out the slot, assuming there is paint affecting the pushing in of the wheel nail?
Or maybe just add weights until the wheel touches the ground?
Should I use Super Glue to keep the wheel in permanently?
This is the boy's first pinewood derby & car so any help would be appreciated.
Thank you.

I have a VW beetle with the originally rims (wheels) and I want to color them black... can anyone give me the process of doing that? I heard sand paper is involved and I could go to Wal Mart to buy the paint.

Thanks also... do I need to take my wheels off or can I do them while their still attached to my car?

I recently had very bad rear brake problem. My rotor was grinding with the caliper and kicking out a very nasty sticky metallic substance all over my rim and side of car. I am looking for some info and products to use to help get this situation taken car of. My main concern is the side of the car, I am afraid I will damage the paint if I do not use the right material. Please help, my caddy looks like a hoopty with this stuff on it.