What should be done after sanding and before painting?

• A. Apply primer
• B. Mask the area
• C. Clean the surface thoroughly
• D. Start painting immediately

Answer: (C)

After sanding, cleaning the surface thoroughly is essential because sanding creates dust and can leave oils, waxes, or fingerprints on the area. If these contaminants aren’t removed, primer and paint may not adhere properly, leading to texture issues, poor adhesion, or defects like fish-eyes and peeling. Cleaning removes dust and residues, leaving a dry, contaminant-free surface that allows primer to bond evenly and paint to lay down smoothly. This step sets up a solid base for the next stages—masking and applying primer—without trapping particles that would ruin the finish. Starting to paint immediately would likely capture dust and oils under the coating, resulting in a rough, uneven final appearance.