Chemicals used for ice and snow removal and dust control can collect on the underbody. If these are not removed, corrosion and rust can develop on the underbody parts such as fuel lines, frame, floor pan, and exhaust system even though they have corrosion protection.
At least every spring, flush these materials from the underbody with plain water. Clean any areas where mud and debris can collect. Dirt packed in close areas of the frame should be loosened before being flushed.
Your dealer/retailer or an underbody car washing system can do this.
Finish Damage
Chemical Paint SpottingChevrolet Cobalt Owners Manual. Removing the Flat Tire and Installing the Spare Tire (All Models Except SS)
1. Do a safety check before proceeding.
See Changing a Flat Tire.
2. If your vehicle has plastic wheel covers, use the
wheel wrench to loosen the plastic wheel nut caps.
Once the plastic wheel nut caps have been
loosened with the wheel wrench, you can finish
loosening them with your fingers. ...